Total Pageviews

Thursday 16 June 2016

How do the nutrients in dead matter become available to leaves?



When something, whether its animals or plants dies, they are broken down by microorganisms (decomposers). These microorganisms are also called saprobionts. These secrete enzymes onto dead tissue, this is called extracellular digestion. They absorb products of digestion. Respiration by microorganisms produces carbon dioxide. Carbon dioxide is then taken into the leaves.

Wednesday 15 June 2016

How can Global Warming effect crop yield?

Global warming is caused by an increase in carbon dioxide - so weirdly, global warming is kind of increasing our crop yields. This is because carbon dioxide is a limiting factor for photosynthesis, so if you increase the amount of carbon dioxide then you increase the amount of photosynthesis which can take place. More photosynthesis means a faster growth rate, more crops and a higher yield. 


What is the carbon cycle?

Carbon dioxide, or CO2 (excuse the missing subscript) is all around us, mainly in the air and water. Plants remove carbon dioxide from the atmosphere as they carry out photosynthesis. Once the carbon dioxide has entered the plant, it becomes carbon compounds within the plant tissues.

Plants are then eaten by animals (the primary consumers) - the carbon is passed on to those animals. It then gets passed on to each successive consumer. Of course, at some point, all of these organisms die - they leave behind carbon compounds in them. Microorganisms called decomposers then digest these carbon compounds. As they feed on dead organic matter, this is called saprobiontic nutrition.

The cycle continues as the carbon is returned to the air and water due to respiration. During respiration, carbon dioxide is released into the atmosphere.

There are times where carbon compounds end up where there's not decomposers - this might be deep oceans or bogs. This means that over millions of years, they are turned into fossil fuels by heat and pressure. When fossil fuels are burnt, the carbon is released - you might know this as combustion.


Wednesday 1 June 2016

Movement of Blood around the Body | AS Level Biology Revision

Arteries:
AWAY from the Heart

to Arterioles


Veins:
BACK to the Heart

Link Arterioles to Veins - CAPILLARIES (tiny vessels)

Arterioles - small arteries
Control blood flow into the capillaries



Path (starting going AWAY from the heart)

  • Arteries
  • Arterioles
  • Capillaries
  • Veins
  • Heart 
Try this mnemonic to help remember the order:
Awesome Andy Cares Very Heroically 

Thursday 12 May 2016

What is visual acuity?

Visual Acuity - The ability to tell apart points which is close together


This is a bit like the resolution of something, you talk about the resolution of an image or microscope. As far as a microscope, the resolution is the smallest distance at which two objects can be told apart.

In your eyes,  Rod cells give low visual acuity because many rods join to the same neurone which means light from two objects close together can't be told apart. In you eye, Rod cells are more sensitive, but cone cells (the other type of cells in your eyes) help you see more detail.



Wednesday 11 May 2016

Why are rod cells so sensitive?

 

Check out my previous post on what photoreceptors are...


o effectively detect light, your eye has two types of photoreceptors, rod and cone cells. Rod cells are the most sensitive to light. They fire action potentials in dim light.




In your eye, many rod cells join one neurone. Essentially, this means that lots of weak signals can combine to reach the threshold and fire an action potential - in scientific terms: many weak generator potentials can combine to reach the threshold so an action potential is fired sooner.




This article specifically relates to AQA Biology Unit 5

Tuesday 10 May 2016

What are photoreceptors?


Before you read this post, you might find it useful to check out my previous post on what a receptor is.


Photoreceptors are light receptors in your eye. Light enters through your pupil. Your eye cleverly adjusts the amount of light which enters the eye using the muscles of the iris.


The light rays are then focussed onto the retina (part of the eye which lines the inside of the eye). The retina contains photoreceptor cells which detect light - from here the light is pretty much turned into messages sent to your brain. One part of the retina - the fovea, contains lots of photoreceptors. Nerve impulses are sent from the photoreceptor cells to the brain via the optic nerve (a bundle of neurones).

Monday 9 May 2016

Sickle Cell Anaemia


Sickle Cell Anaemia is a recessive genetic disorder, it's caused by a mutation in the haemoglobin gene. This causes an altered haemoglobin protein to be produced. This means the red blood cells become sickle shaped (concave) - not the typical shape you're probably aware of. The red blood cell's concave shape means they can't flow through capillaries easily like normal red blood cells can so the capillaries can become blocked - blood flow is then restricted. This can also bring up so many more issues like organ damage and periods of acute pain.

Some people can be carriers of the sickle cell gene, amazingly, carriers of the sickle cell gene are partially protected from malaria. Because of this advantageous effect, the frequency of the sickle cell gene have increased. Unfortunately this means the likelihood of inheriting two copies of the allele are increased - overall, this means sickle cell anaemia is more prevalent in these areas.
 

Thursday 28 April 2016

AS Revision - DNA Replication

Mitosis: (used for growth and repair, including the growth of the foetus)


2 daughter cells produced
Identical to original (parent) cell and to each other, unless a mutation occurs.

Importance:
  • Increase in number of cells
  • 2 haploid cells fuse to make a diploid cell
  • Differentiation
  • Replacing cells (when they're damaged or die new cells must form to be genetically identical to function effectively)
Interphase: (cell not dividing, when replication of DNA occurs)
  • cell continues its normal function
  • prepares to divide
  • Cells DNA is unravelled and replicated - genetic content is doubled
  • Organelles replicated so there's spares
  • ATP content increased
Prophase:
  • Chromosomes condense (they get shorter and fatter)
  • Centrioles start moving towards opposite ends of the cell forming a network of protein fibres across it (forms the spindle)
  • Nuclear envelope breaks down
  • Chromosomes are free in the cytoplasm
Nuclear envelope: membrane around the nucleus
Centrioles: tiny bundles of protein

Metaphase:

  • Chromosomes (each have two chromatids) line up along the middle of the cell
  • become attached to the spindle via their centromere
Anaphase:

  • Centromeres divide
  • separating each pair of sister chromatids
  • spindle contracts
  • Pulls chromatids to opposite ends of the cell (first the centromere)
Telophase:
  • Chromatids reach opposite poles on the spindle
  • uncoil and become long and thin again
  • They're now called chromosomes again
  • Nuclear envelope forms around each group of chromosomes so there are now 2 nuclei
  • Cytoplasm divides
  • FORMING: 2 daughter cells genetically identical to the original cell and to each other
Mitosis is now finished and each daughter cell starts interphase and the whole cycle repeats.

Mitotic index = the number of cells carrying out mitosis (visible chromosomes)/ total number of cells on the slide

Cancer:
(result of uncontrolled cell division)

  • cell growth and cell division controlled by genes
  • cancer is a tumour that invades surrounding tissue
  • cells keep on dividing to make more tissue (the tumourr)
Chemotherapy:
  • prevent the synthesis of enzymes needed for DNA replication
  • Not specific- can kill normal cells, steps taken to reduce the impact on normal cells
  • A large portion of the tumor is removed using surgery
  • Repeated treatments (ie not one big dose), treatment breaks in between. 

G1- cell growth and protein production


specifically for AQA Biology AS Unit 2

Wednesday 20 April 2016

What is a synapse?


When electrical impulses are fired around your body, they do so by travelling around in neurones as chemical/electrical impulses.


However, your neurones don't cover every inch of your body. To get over this issue, there are small gaps between the neurones - this is called the synapse. Technically speaking, it's a junction between the neurone and the next cell. , the gap itself is called the synaptic cleft. The neurone before the gap is given the name of a presynaptic neurone - it has a swelling on it called the synaptic knob. On the presynaptic neurone there's synaptic vesicles filled with chemicals called neurotransmitters.


When an action potential reaches the end of the neurone, neurotransmitters are released into the synaptic cleft. They diffuse across this gap and attach to the postsynaptic membrane - here they bind to specific receptors. When the neurotransmitter binds to the receptors, this could trigger an action potential, causing muscle contraction (perhaps) in the next cell. Alternatively, a hormone could be secreted if it's a gland cell.




Because these receptors are only on the post synaptic membrane, this makes action potentials unidirectional - i.e they travel in only one direction. If nerve signals travelled in multiple directions, things would get very confusing very quickly!

Monday 18 April 2016

What are genetic mutations?

 


Mutations happen all the time - most are absolutely harmless, some are harmful - but what are mutations?


A mutation is a change, deletion or addition of a base in a DNA code. Your DNA is a long 'string' if you like of complementary bases - these code for amino acids and in turn, these code for proteins. If one of the bases are substituted this doesn't always lead to a change in amino acid formed. This is because your DNA is degenerate. This means that more than one combination of three bases code for one amino acid.


A deletion of a base will change the amino acid coded for. This is because it causes a 'frame shift' - this moves all the bases up in the sequence - different amino acids are coded for. This in turn, affects the hydrogen bonding between the complementary base pairs. Because the hydrogen bonds are altered - this affects the tertiary structure. This means the protein produced isn't functional.


The real issues occur if mutations occur within the genes which control cell division - these are called, the "tumour suppressor genes" and the "proto-oncogenes". If mutations occur within the proto-oncogenes, then cell division is stimulated. It is uncontrolled cell division which leads to the formation of tumours and potentially cancers.



 

Saturday 16 April 2016

What is tRNA? | A- Level Revision

  • tRNA is a type of RNA
  • single polynucleotide strand
  • folded into a clover shape
  • hydrogen bonds between specific base pairs hold the molecule in space
At one end:
  • specific sequence of 3 bases called an anticodon
At the other end:
  • amino acid binding site (complementary base pairings)
Function:


  • tRNA found in the cytoplasm
  • involved in translation
  • carries the amino acids (used to make proteins) to the ribosomes




Thursday 14 April 2016

Panda Genetic Fingerprinting



Using Genetic Fingerprinting to save the Panda might seem like a crazy idea but it's an idea that might have legs! The giant panda is one of the rarest animals in the world and is considered to be on the brink of extinction. Giant pandas have been kept and bred in zoos for many years now. In many areas, Panda's are on breeding programmes so they could, one day, be released into the wild.



Unfortunately, zoo life doesn't come worry free. There's the issue that with small populations, genetic variation is reduced. This basically means they could well struggle when they're released into the wild. Having said that, Pandas find it difficult to reproduce in captivity.


Scientists can only guarantee that a female will get pregnant through pretty much carrying out Panda IVF. When they do so, they use sperm from several males. One problem with this is that, who's the father? Identifying who the father is can then help the scientists to identify how genetically different pandas are.

Their method of obtaining DNA samples is strange, to say the least!! They collect around
10 Panda faeces can be collected from the wild. The faeces contain DNA from the panda, from the bamboo on which they feed and from bacteria. The DNA is then put through the 
polymerase chain reaction (PCR). The primers used attach only to the panda DNA because of complementary base pairings.

The DNA from this, then goes through genetic fingerprinting. This is where the genetic sequences are read (ie GATC etc etc). Collating an idea of what happens in the wild, pandas can then be individually identified.

How this happens, is quite a complex scientific process. DNA is first cut using a restriction enzyme. This cuts the DNA at specific points. Gel Electrophoresis then separates the strands according to length (so mass as well). A process called Southern blotting then makes the strands single stranded. A DNA probe (which is complementary to part of the DNA strand) is then added. The probe will act as some kind of marker - it could be radioactively marked or fluorescent.









Wednesday 13 April 2016

Antibiotics | Biology A-Level Revision


  • In normal cells water enters by osmosis - too much water, the cells burst (osmotic lysis)
  • Bacterial cells have a tough cell wall which prevents the cell from expanding
  • Antibiotics stop the bacterial cell wall from forming correctly so the wall is weaker. 
  • This weakened cell wall means that the cell can burst due to osmotic lysis so the bacteria doesn't spread
Although there's a new problem, antibiotic resistance:
  • Shortly after antibiotics were discovered, small groups of people were developing resistance due to a chance mutation. 
  • The mutation caused the production of a new enzyme which broke down the penicillin. 
  • The gene that coded for this mutation then is passed to the next generation (through vertical gene transmission) 
  • The antibiotic resistance gene carries plasmids so it can pass onto other bacterial species via horizontal gene transmission. 
Why do bacteria need to adapt?
Similarly to what Darwin said, only the fittest survive, so to increase their chances of survival, they need to adjust to suit their environment. What this does mean however is that antibiotics can quickly become useless as the bacteria adapt to become resistant to them.

Conjugation

  1. A donor cell produces a thin conjugation tube between its cell and the recipient cell. 
  2. The donor cell replicates its plasmids
  3. The plasmid is unwound so it's now straight and can fit through the conjugation tube
  4. The replicated plasmid moves through the conjugation tube and enters the recipient cell
  5. The plasmid which has just entered the recipient cell now returns to a circular shape
  6. The bacteria has now replicated. 


Key terms:
  1. Mutations: A random change in the quantity or structure of DNA (one base is added,deleted or replaced)
  2. Conjugation: The fastest method of evolution where DNA of existing individuals is combined - horizontal gene transmission
  3. Plasmids: A circular piece of DNA
Vertical Gene Transmission - DNA passed to the next generation of the SAME species
Horizontal Gene Transmission - DNA passed to different species via CONJUGATION

What is cholesterol?

 


We always hear about cholesterol - pretty much why too much of it's bad, and they're not wrong. There are two types of cholesterol, both good and bad. It's a soft and waxy material found in the membranes of cells. From here, it's transported into your blood stream. Partly, this is a substance produced by your body and partly absorbed from animal products you eat, this includes eggs, meat and dairy products.

The bad cholesterol is obviously the stuff we should try and limit, this is because it can clog blood vessels. The issue here, is that it increases your risk of heart attacks and strokes. Good cholesterol however removes the bad cholesterol. It takes it to the liver to be destroyed. This means that if you've got a lot of good cholesterol in your system, it actually works to protect your body from heart disease.

Friday 8 April 2016

What are mutagenic agents?

Mutations are spontaneous errors where DNA is misread during replication. There are some things which can increase the rate of mutations. These include UV, ionising (high energy) radiation, some chemicals such as benzene and some viruses are all examples of mutagenic agents. They work by

acting as a base. Chemicals called base analogs can then act as a substitute for a base during DNA replication.


Monday 4 April 2016

Maria Sharapova - The Debate


There's a whole number of ways someone can flip Maria's failed drugs test. For pretty much her entire career, she's been at the centre of tennis. She's won five grand slams and an Olympic silver medal at London 2012. She's 28.








If you take Sharapova's statements literally, then it was an honest mistake - stupid at least. From what she said at last Monday's press conference, she says she received the list as an email attachment from Wada. She says she didn't open up the email. There are so many ways you can look at this, how much trust do you place in your doctors? This is where sports psychology comes in - does this place unnecessary stress onto someone who has to perform day in, day out?










Having said that, if you look more closely at what this drug actually is, it appears as though it's one which you only take for about 2 weeks at a time - why was she taking it for 10 years?










Legally speaking, this now falls to the ITF, WADA and her team to investigate what happened and the circumstances leading up to this. She'll be given a suspension (pretty much for certain), it just falls to this investigation process to determine whether she deliberately took the drug knowing it was banned or took it without knowing it was banned which would class as negligence. According to WADA it was added to the banned list because of "evidence of its use by athletes with the intention of enhancing performance".





Whatever you believe, we'll doubtless hear the truth eventually!







Wednesday 30 March 2016

Marmosets | Animal Profile



Marmosets, are very small, but very cute monkeys. They're only around 22cm long, there's about 22 subspecies of them.

Compared to other monkeys, they show some very different features, they have claws rather than fingernails and strong hairs on their wrists. Unlike us, they don't have any wisdom teeth. 

Their body temperature is unbelievably variable, changing by up to 4 °C in a day. Marmosets are native to South America and have been found in Bolivia, Brazil, Colombia, Ecuador, Paraguay and Peru although they've been spotted in Central America and Mexico. Unfortunately, they have also been raised as pets.

Saturday 26 March 2016

ANIMAL A-Z: OUT NOW!!!!

My new book, an A-Z guide to some of the hidden gems of the Animal Kingdom is OUT! Check out the links below:
 
 

Friday 25 March 2016

MY NEW BOOK! ANIMAL A-Z!!

My new book, an A-Z guide to the Animal Kingdom will be released in the next couple of days on Amazon and Amazon Kindle. The book contains a huge range of animals, from the weird to the wonderful and everything in between. Below is a selection of animals from the book:

  • The Aye-Aye
  • Antelope
  • American Alligator
  • The Tarsier
  • Porpoise
  • Seals
  • Puffins
  • Tasmanian Devil
  • The Quagga
  • Tigers
  • Lions
  • Sea Lions
  • Clownfish
  • The Yellow Billed Hornbill
  • The Uakaris

There's this and a whole lot more in my book! When it's released, I'll add a link here so you can check it out :)



 

What is an ectotherm?

 

An ectotherm is an animal (perhaps a reptile or fish) which can't control their body temperature internally - they control their body temperature through their behaviour. This might be through a number of ways - including physically moving from one place to another, so from direct sunlight to shade so they don't overheat.

In the case of ectotherms, their internal temperature depends on that of their surroundings and their activity level depends on the external temperature. They're more active at higher temperatures and less active at lower temperatures.

As far as their metabolic rate is concerned, it's variable and they generate very little heat themselves.
 

Tuesday 22 March 2016

Survival Responses in Plants

Another type of growth factor are auxins. Auxins stimulate growth of shoots by cell elongation. This is where the cell walls become loose and stretchy, the cell then gets longer. At a high auxin concentration, auxins inhibit growth in the roots. A specific type of auxin, Indoleacetic acid (IAA) is an important type. It's produced in tips of shoots in flowering plants. As the plant works to control it's growth and respond to the stimuli, IAA is moved around. It moves by diffusion and active transport over short distances, across longer distances IAA is moved via the phloem. Different levels of IAA across the plant results in uneven growth of the plant - this means the plant then grows towards the light for example.

Plants, particularly flowering plants need to respond to their surroundings like animals do, in order to increase their chances of survival. They can sense gravity so their roots grow in the right direction. They also respond to light so they can maximise the amount of light they receive for photosynthesis. Plants which climb have a sense of touch, they find things to climb so they can reach the sunlight.


Tropism is this response to directional stimulus. A directional stimulus is just a response to a stimulus coming from one direction. Plants respond to this stimulus by regulating their growth. Positive stimuli is growth towards the stimulus, negative tropism growing away from the stimulus.

The plants responses are brought about by growth factors - pretty much like the plants hormones. This is because they don't have a nervous system like us. They also don't have a circulatory system, hence the reason why growth factors can't be called hormones. Growth factors are chemicals which speed up or slow down plant growth. They're produced in parts of the plant which grows (the shoot tips and leaves). Once they've been made, they move to where they're needed in the plant. One example of a growth factor is gibberellin, this stimulates flowering and seed germination.
 

Sunday 20 March 2016

What is a receptor?

A receptor is an organ or cell which can respond to light, heat, or another external factor. They transmit an electrical impulse to the sensory nerve - this kick-starts the reflex arc.  There are many different kinds of receptors, all of which are specific to one kind of stimulus, they're all given names:


Mechanoreceptors - detect mechanical stimulus like pressure/vibrations
Thermoreceptors -  detect heat
Baroreceptors - detect high/low blood pressure in the heart
Chemoreceptors - detect chemical changes in the heart, so a change in oxygen, carbon dioxide or pH level




Fun Fact:

The retina of the octopus has up to 20 million light receptors :)



Friday 18 March 2016

What is diabetes?


Diabetes is a condition which means your blood glucose levels are very erratic without intervention. There are two types - type 1 and type 2.

If you've got type 1 diabetes then the beta cells don't produce any insulin. After eating, the blood glucose levels rise and stay high - this can cause hyperglycaemia, this could be life-threatening. The kidneys can't absorb all the excess glucose so some of it's excreted in the urine. Type 1 Diabetes is treated through regular insulin injections, these, of course, need very careful monitoring because too much could cause a dangerous drop in blood glucose - hypoglycaemia. On top of that, a carefully monitored diet and controlling simple carbohydrate (glucose) intake can avoid sudden rises.

Type 2 diabetes is often acquired later in life and in most cases, is linked with obesity. In this case, the beta cells aren't producing enough insulin, or the body's cells aren't properly responding to the insulin. The cells might not be responding properly to insulin because receptors on the cell membranes may not be working properly. In short, the blood glucose level is higher than normal. This type of diabetes can be controlled by eating well, loosing weight and monitoring glucose intake. If all else fails, glucose lowering tablets can be prescribed if weight-loss and diet control can't control it.
 

Thursday 17 March 2016

Big Cats vs Little Cats Part 1







Over the course of evolution, cats have gone from an apex hunter to living room lounger. These cats have got a lot in common with their fearsome ancestors. If they were bigger, they’d probably try to eat you – or would they?
 
When you think of the tiger or lion you probably think of a big dangerous cat, a crazy man eater. They can actually be super friendly and super nice. Granted, they can be aggressive, but it’s not the first thing I’d think of. They’re socially dependent, loving and affectionate creatures who need food!

When you look at Lions, they’re continually giving off communication all the time- professionals can easily get tuned into the small signs that Lions continuously give off. They’ve got little tale –tale signs, a rhythmic twitch for example. Even something as simple as yawning is quite a complex sign. Not always, but a lot of the time, Lions yawn to ‘show off’ their teeth – pretty much a dominance thing.

Your cat uses its own body language to communicate like a lion, except they’ve got one major difference. They have fewer facial muscles so they find it harder to communicate the way a lion does – domestic cats use their tongue, mouth, tail and ears to communicate.  Tail up – your cat is happy and approachable. Unlike dogs, if they’re ‘wagging’ their tail, they’re agitated. Surprisingly, I’d avoid giving your cat direct eye contact. This sends then mixed messages and even is a sign of aggression. If you blink slowly, you’ll reassure your feline friend, you’re not a threat and only in it for the cuddles! It also has the benefit, they’ll trust you!

The domestic cat is the latest addition to the cat family – a product of 10 million years of evolution. A lot of what your cat does comes from their wild relatives. Our cat has a huge love of acrobatics – an ability which has its roots in South East Asia- the birthplace of all cats. This hot and humid climate with trees up to 100m high was a perfect location for cats to hone their acrobatic skills. In this climate, climbing trees was the best way of getting food.

Over this period, cats evolved to leap and to swing through trees – reaching up to 40mph – quick enough to hunt birds and monkeys. One cat still lives in the treetops just like its ancestors, the Clouded Leopard, so rare we don’t know how many are left in the wild. Breeding centres are one of the only places to see these elusive Clouded Leopards. Its spotted coat makes for perfect camouflage amongst the dappled jungle light.

The Clouded Leopard’s tail is often longer than their body, this means they can balance like a tightrope walker, elegantly dashing through the trees.

Our cats have some of these amazing adaptations for climbing; they’ve got hooked claws up to 5cm long. They can grip most surfaces, their paws sense vibrations to check the route is safe.
 

Cats are one of the only animals born without a fear of heights – they’ve got one issue though! Unlike a lot of other animals, their front facing paws mean they can’t climb down easily. Some cats can get away with this because they’ve got rotatable paws. This is the reason why thousands of our pets get stranded high up in our trees every year.  When they get in that situation, where they are stuck - some cats pick leaping as their best option.

All of our cats have acquired some of the Clouded Leopards climbing abilities. Clouded Leopard kittens spend almost every waking minute playing – this is how your cat learnt too. Much like us they get the hang the hang of things by observation and repetition. When cats play, ‘happy’ chemicals are released in their brain; this encourages them to carry on playing and learning. One major game our cats enjoy – even through adulthood is stalking prey. They stalk it until they get close enough to pounce. They’re skills are so advanced that the prey rarely sees it until the cat until it’s too late.
 
 

Wednesday 16 March 2016

ANDi the Monkey


ANDi was the first ever genetically modified monkey. He was given the name ANDi because it's backwards for inserted DNA. Whilst he was still an unfertilised egg, he was given a simple marker gene which can be easily identified within his genetic blueprint. The idea being, that we can then have laboratory animals carrying genes associated with specific medical issues.


The Scientist's goal was to show that a foreign gene could be inserted into a primate's chromosome to produce a functional protein. They chose this gene in particular because it emits a fluorescent green glow easily seen under a microscope. They then took tissue samples from ANDi's cheek, hair and umbilical cord. These samples confirmed the presence of the gene - but they could see no green protein. This could be for a variety of reasons, some as small as the quantity of the protein could be too small. They also say that some genetically modified animals don't start producing the foreign protein until after they're a year old.


Other than that, it looks as if he's perfectly normal, happy, healthy, playing with other monkeys as he should - enjoying monkey life!

Monday 14 March 2016

British Science Week 2016


Science week is a ten day celebration of all things Science, Technology, Engineering and Maths. Across the UK more than 1.6 million people get involved with events nationwide - getting inspired. Over this week, I'll be posting some of my favourite parts of science.

Follow me!
Twitter @Sci_Sparks
The Young Scientists Journal : @YSJournal

What is Meldonium? | Drug Profile

Meldonium was banned because it aids oxygen uptake and endurance.

Meldonium, sometimes called mildronate, taken by Maria Sharapova for virtually 10 years was originally designed to treat ischemia. Ischemia is a condition in which there's a reduction in blood supply to the body tissue, it also might have benefits for diabetes sufferers.

Meldonium adjusts the body's use of energy, stimulating glucose metabolism and helping to clear a fatty build up in arteries. You can get Meldonium mainly in Russia and Latvia but the drug is banned in the US.

Surprisingly, the drug was often given to Soviet troops in the 1980s to boost their stamina whilst fighting in Afghanistan. Since Maria's story came out, the manufacturers of Meldonium have come out to say the normal course of treatment is 4-6 weeks. Having said that, this all depends on dosage.

Of course, the level of the benefits depend on the dosage, something of which Maria Sharapova will need to provide strong evidence of when she goes before an ITF panel.
 

Sunday 13 March 2016

What is homeostasis?


Animals (including us) use a system called homeostasis to maintain a constant internal environment. This keeps temperature, pH and blood glucose level all constant.

There are a number of systems in place to keep this all level, these are called homeostatic systems. They detect a change and respond by negative feedback. The systems involve receptors (these detect the changes), a communication system (to communicate the changes) and effectors which make the change.

Hypothermia occurs when the body temperature is too low, this involves positive feedback. Below 35C and you're hypothermic. It happens when heats lost from the body quicker than it can be produced. As body temperature falls the brain doesn't work properly, shivering stops and the body temperature falls even more - basically, you're in trouble!

Positive feedback takes the body temperature further away from the normal level, body temperature continues to decrease unless some action is taken! - this system of positive feedback isn't involved in homeostasis because it doesn't keep your internal environment constant.
 

Thursday 10 March 2016

How does you brain control your heart rate?

Your heart is a muscle, it pumps blood around your body as it contracts. Inside your heart is essentially a network of nodes and vessels, these help nerve impulses from your brain tell it when to contract.

One of these nodes, the SAN (sinoatrial node) generate these electrical impulses which cause the heart to contract. The rate at which the SAN works (essentially your heart rate) is unconsciously controlled by part of your brain called the medulla. Animals (including humans) alter their heart rate to respond to certain stimuli - for example, your heart will beat faster if you've just been running. This system ensures that your body receives enough blood and oxygen to function.

For the body to respond to something, it first needs to be detected. There are two main types of receptors which help to control  heart rate - baroreceptors and chemoreceptors.

Baroreceptors - these detect pressure in the aorta and vena cava. They're stimulated by high and low blood pressure. If you think about barometers which detect atmospheric pressure changes, that's essentially what a baroreceptor does, just in your heart!

Chemoreceptors - these are chemical receptors, they're found in the aorta and carotid artery (a major artery in the neck) and also in the medulla. The chemoreceptors monitor oxygen level in the blood, carbon dioxide level and pH. Knowing the pH level is very useful because its an indicator of oxygen level.

Once these receptors detect a change, electrical impulses are sent to the medulla along sensory neurones. The medulla processes this information and sends impulses to the SAN and the heart rate is adjusted.

This post specifically relates to AQA A-Level Biology Unit 5 - Responding to the Environment

Wednesday 9 March 2016

What are Fertilisers?



I'm sure we've all either used fertilisers or been around your parents when they've been using fertilisers. Fertilisers provide crops with chemicals needed for growth, like nitrates. This is because crops use up minerals as they grow and the soil can't usually supply enough minerals to fulfil demand.


There are two main types of fertilisers - natural and artificial. Natural fertilisers are made up of organic matter - like manure and sewage sludge. These don't have a set combination of minerals - there's no 'recipe' pretty much just because they're natural.

Artificial fertilisers are man made using inorganic material - unlike natural fertilisers there is a 'recipe' and the recipe depends purely on what you're growing and where you're growing it. These contain pure chemicals like ammonium nitrate in the form of powders or pellets.


Whether they're artificial or natural, they provide crops with the minerals they need for growth, like nitrates. Over time, this level needs to be replenished because they use up the minerals as they grow. The job then falls to the farmers who decide how much to use, too much is too expensive, too little and it would get washed away before it had an affect.  

When fertilisers are washed off of fields (leached), this causes the problem of Eutrophication. Excess fertiliser causes an algal bloom, this blocks light, in turn, it reduces photosynthesis. This means that submerged plants can't carry out photosynthesis, they can only respire so die. Saprobiotic microorganisms aerobically respire, over time the oxygen supply is depleted and fish also die.



This article specifically relates to AQA A2 Biology Unit 4

Monday 7 March 2016

Maria Sharapova: "I've failed a drugs test" | What is Meldonium?


Former world number one, Maria Sharapova has been taking a drug called Meldonium for 10 years. On January 1st, this year, it was entered on the banned list – Sharapova wasn’t informed and she failed a drugs test at the Australian Open.

She’s been taking it since 2006 due to persistent health issues, now, the five time grand slam champion’s not aware of the sanctions she’ll face as a consequence. Since Wimbledon last year, she’s only played four tournaments. This year, she’s only played the Australian Open. She’s currently struggling with various different injuries but it’s likely this revelation will have an even bigger effect on her 2016 schedule.

It’s quite a controversial drug – it’s used in Russia and Lithuania but USA hasn’t approved the drug. Clinically speaking, it was first used to treat angina and myocardial infarction (heart attacks). It’s also been known to help treat diabetes and some neurological issues. In her press conference, Maria said that she’s got quite a large family history of diabetes. More recent reports suggest that it can improve learning and memory. Weirdly it might also have an effect on testosterone and men’s health.

As far as sport is concerned – this is a metabolic performance enhancer. This basically means that Sharapova - amongst the health benefits she was already taking the drug for, would have an enhanced energy and a stronger heart muscle. In short – she’d have more energy and be able to last longer on the tennis court. It also would have had an improvement with movement coordination and concentration. It also has a positive effect on the energy metabolism of the body – activating the central nervous system.

At this stage, it’s unclear as to what sanctions she would face, the ITF (International Tennis Federation) in conjunction with WADA (world anti-doping agency) will look at various different factors like who gave the drug to her, was she aware of the effects? Whatever sanction she’ll face she, and her team have got  lot of explaining to do.



 

Glow in the Dark Cats


This might seem a little odd - and a little like someone has just done a pretty good photoshop job, but I promise this is all true! Scientists have actually "created" glow in the dark Cats, Monkeys and fish. In 2007 South Korean scientists inserted the glow in the dark gene then cloned these cats. The end result? Fluffy, florescent felines! They did this through taking samples of skin cells from Turkish Angora cats. They then used a virus to insert genetic instructions for making a red florescent protein. They put this altered nuclei back into the eggs for cloning. You might now be thinking - what's the point? Well, scientists are hoping that they could, eventually create laboratory animals with human genetic disorders - although this does of course, create a massive ethical issue!

Thursday 3 March 2016

How big of an issue is hearing loss?




Thankfully, I don't know anyone who's got hearing loss (or at least hearing loss which isn't selective!! :)) But according to the World Health Organisation, this is a very big issue. In fact, today is World Hearing Day. Here are the stats...





32 million children worldwide have disabling hearing loss
60% of cases are preventable - only 17% are from birth related causes.
31% of hearing loss cases result from infections



Make sure you're aware of the symptoms to prevent any issues escalating.

 

Wednesday 2 March 2016

What is Global Warming?

We hear about global warming all the time - our planet is unique in the sense it could well be the only one with life, so we need to preserve it. But at the moment we're damaging it. This is partly the aim of the UN's Global Goals. This is to ensure that future generations get to enjoy our planet too. Global warming is caused by increasing carbon dioxide levels - this leads to an increase in average global temperature.

Human activity has caused global warming by enhancing what's called the Greenhouse Effect. This is because, greenhouse gases absorb outgoing energy so less is lost to space. To some degree, the greenhouse effect essential to keep planet warm but too much and planet warms up.

The two most common greenhouse gases, carbon dioxide and methane are to blame for this increase.


Burning fossil fuels, farming and deforestation all increases atmospheric concentrations of carbon dioxide. This  effects all organisms and we need to do something about it!

Scott Kelly's Return to Earth | #TimPeakeUpdate


Tim Peake's had some major changes on board the ISS recently - early this morning Commander of the Space Station, Scott Kelly returned to earth after a staggering 340 days in space. He left Earth early last year and hasn't been back since. The job now lies in figuring out Earth - and the minor change of gravity!


Only one person has beaten this record of 340 days which Scott shares with two other Russian crewmates - Valeri Polakov who spent 14 months aboard the Mir Space Station. What's even more special about Scott's time in space is that now, NASA can look at what 11 months in space does to his body, with Scott's identical twin and all because Scott's twin is genetically identical they can directly compare what 11 months in space does to your body.


Across his year in space, he's tweeted 1,000 images, worked on hundreds of experiments, carried out many space walks and above all he's looked at our planet in a totally new way. Follow @StationCDRKelly as he rediscovers planet Earth.




Thursday 25 February 2016

What is siRNA?



siRNA is short for small interfering RNA and acts to 'silence' a gene. It's short as its name suggests, they're usually only around 21 nucleotides long. They're also double stranded. This means that they are made up of a series of two complementary base pairs.


siRNA is called "interfering" because it disrupts translation (a part of protein synthesis which takes place within the cytoplasm). The siRNA and accosiated proteins bind to target mRNA
proteins cut mRNA into sections so it cant be translated.


siRNA prevents expression of the specific gene as its protein cant be made during translation so the protein isn't made.

Sunday 21 February 2016

Polar Bear

Polar Bears in the UK? Sounds strange but we're going to try and breed them in Scotland later this year. The last time we attempted to breed Polar Bear cubs was 25 years ago.
 
The Royal Zoological Society of Scotland have begun preparing for the arrival of two bears at Highland Wildlife Park near Aviemore. In the wild, make and female polar bears live separately. In order to mimic this in the park, a crate was placed in the male bears' enclosure which will be used to transport Arktos to where the female. They hope that this tactic will mean they can pair the two up without the use of a sedative.

 

Wednesday 3 February 2016

What are allergies?


Loads of people have allergies, some are just an annoyance others are worse. In the worst case, it can be life threatening. An allergy is an immune system response to otherwise harmless substances such as pollen, some foods or dust. Even though these aren't harmful substances, the body identifies them as a threat and responds to them. The immune system "fights" the allergen, upon the following exposure the same response is triggered.

There are many ways of managing allergies, some as simple as avoiding the allergy or medical treatments like immunotherapy. The most common of which, is to take a form of anti histamine, this lowers the level of histamine in the blood, decreasing any symptoms you might be suffering from.




Monday 1 February 2016

What is succession?



Succession takes place if there is a very hostile environment - by hostile, I mean pretty much inhabitable. Firstly, the pioneer species colonize the area, because they've colonized the area this causes a change in the environment. So if the pioneer species are plants then the fact they're photosynthesizing changes the environment - this change makes it less hostile to other organisms. This enables other species to colonize so the biodiversity of the area increases. This means the number of the pioneer species decreases. Going forward a good few years - the stability has now increased to a point where the environment is no where near as hostile as it was and a climax community has now reached.


Wednesday 27 January 2016

How intelligent are gorillas?





The thing with intelligence is that it's hard to measure intelligence against different animals. Some might be able to do things others just can't do. Gorilla's intelligence is displayed through their ability to make natural materials to help them gather food more efficiently. In particular, Gorillas are known for there selective ability to select branches based on length - remove leaves from them and show incredible dexterity.Scientists reckon that this level of intelligence matches that of a young child. Some Gorillas are known to have particularly high intelligence levels. Take a Western Lowland Gorilla that lived in Buffalo Zoo in 2009 for example. This Gorilla actually used a bucket to collect water. An experiment was actually carried out in 2010 where a group of them were given five gallon buckets - two of the younger gorillas were able to successfully fill the buckets up. Another gorilla in particular, Koko has been taught and mastered over 1000 signs from American sign language. Although  these signs have been simplified to get around the issue of the gorilla not being able to form as complex hand signals. However intelligent you think Gorillas are, it definitely makes you realise that Gorillas and other animals have a very different kind of intelligence!



Saturday 23 January 2016

The Lost Clownfish

 

There are a number of problems which can arise as a result of Ocean Acidification - neurological problems in fish, are one of them.
 
Scientists have discovered that a lower pH can also affect neurological problems. A study showed that some young clownfish have lost the ability to navigate home because of changes to their sense of smell. This is because the fish can be attracted to smells they’d otherwise avoid, leading them to predators or leading them far away from their home. Scientists believe that the reason behind this is because of changes in a neurotransmitter in higher carbon dioxide levels. They also found that this might be reversible with the addition of a chemical. Although adding chemicals could be very costly, particularly as it would need extensive testing to make sure it wouldn’t harm other species. 

Wednesday 20 January 2016

The Great Salmon Rush

Grizzly Bears are part of one of nature's greatest events, every year they gather, all to get the best catch. Check out this video of the event - it's quite incredible!

Check out my previous post on Grizzly Bears 



Tennis Match Fixing - what's the story?

Andy Murray (L) Jo Konta (R)
There's been one huge story in the world of tennis recently - match fixing. These reports have resulted from a joint Buzz-feed - BBC report. The report basically said some of the world's top players (both past and present) have been paid a substantial amount to loose a match. The matches in question were at all levels of the sport, both smaller tournaments and grand slams - including Wimbledon. The report specifically mentions a list of 16 players who are, or have ranked inside the top 50. The players in question have been flagged to the Tennis Integrity Unit.

The first thing you're probably thinking is why would a tennis player want to throw a match? The main thing is probably due to the fact if you're ranked around 50 in the world, a person or organisation offering thousands is going to be more than any potential prize money.

The other main question is that how do you detect this kind of thing and how do you stop it? Well once a potentially dodgy match is flagged the betting odds of the match are examined. So if player X goes from 80% likely to win to 40% likely - alarm bells ring. Of course there are so many variables - like injuries and the stage of the match to take into account.

The reason why huge changes in betting flagged is because there are known syndicates in Russia, northern Italy and Sicily who have placed thousands on particular matches. When there are huge bets placed - the odds swing.

Since these reports have broken many tennis players have had their say on the matter -  Andy Murray has said both youngsters and older players need to be educated over betting, Novak Djokovic has said he was once approached but has never fixed a match whilst Roger Federer wanted to hear names because the evidence so far isn't concrete enough.

And okay - I totally realize that whilst the report says this is a huge issue we can't continue speculation. The report should be used to trigger change within the Tennis Integrity Unit rather than to guess who has been match fixing.  

Monday 18 January 2016

The Space Flower | #TimPeakeUpdate


Embedded image permalink

The ISS crew have made another breakthrough with their scientific exploration - they've grown a space flower. This is actually the first ever flower which has bloomed in space. This particular flower is a Zinnia flower. In December, ISS Commander - Scott Kelly tweeted an image of the plant wilted and mouldy, but the crew successfully worked their magic - and it bloomed! :) You might think, what's the point? Some plants are grown on the ISS for educational outreach - like this one! Others are grown as food for the crew - in actual fact  they grew lettuce which was ideal for the crew because they could have fresh lettuce! It might not sound like much, but when you've been eating space food for a while, fresh lettuce must taste amazing! It also opens up a whole load of avenues when it comes to maybe feeding a growing population.

Sunday 17 January 2016

Grizzly Bears

Scientists classify any North American subspecies of the brown bear as a grizzly bear – although they’ve actually assigned them the name of a “North American Brown Bear”. However it was first given the name of the Grizzly bear due to its characteristic long, ‘grizzly’ hair. Characteristically, they’re very solitary, active animals. They gather once a year for the “great salmon run”- where they gather at rivers to catch the mass migration of salmon. These bears have one of the lowest reproduction rates across the whole of North America. This is due to many reasons, one being that they reach sexual maturity at around 5 years old – a lot later than most land mammals in North America. When they do reproduce, a female bear produces on average 2 cubs a litter. Once the cubs leave or are killed, the female might not produce a second litter for perhaps 2 or 3 years later.

Surprisingly, Grizzly Bears play a huge ecological role; they have mutualistic relationships with some plants, spreading their seeds. The bears actually help by increasing species diversity in the plants on the forest floor.

Friday 15 January 2016

What is Speciation? | A Level Biology Revision

Speciation is pretty much the evolution of new species from existing species. A species being a group of organisms with similar genes which are able to interbreed to produce fertile offspring. If populations become seperated (geographical isolation) then they are no longer able to interbreed. This might be for a number of reasons  - lets take a huge mountain for example. Selection pressures will be different in both locations, for example ease of getting food or temperature may differ. Within these slightly different environments some are better able to compete than others - this  causes the allele frequencies to change in each population. The genes then, over time become so different they now can't interbreed.

Other keywords:

Stabilizing selection - this is selection which tends to favor the average (gets rid of the extremes)
Directional selection - this favors one extreme

This is specifically for AQA A Level Biology Unit 4