The Digestive System and Enzymes

You got this far without knowing what an enzyme is? Lies. But i'll cover it after this and then you will have to go back and read it all again to link up the enzyme to the properties. Forced double revision.

You need to know about quite a few places in the body though:

Mouth

• Food is moistened with saliva (comtains amylase enzyme that breaks down the starch)
• Food chewed to form bolus (ball-us... caus it's a ball of food... get it?)

Oespohagus

• Tube that takes food from mouth to stomach (peristalsis)

Liver

• Where bile is produced (neutralises stomach acid to allow enzymes to work)

Gall Bladder

• Where bile is stored (then released into small intestine)

Small Intestine

• Produces protease, amylase and lipase. (to break down food and aid digestion)
• Where energy from food is absorbed out into body

Stomach

• It pummels the food with its muscular walls (grrr... so manly)
• Produces protease enzyme (called pepsin)
• Produces hydrochloric acid
• To kill bacteria
• To give the right ph for the protease enzyme to work

Pancreas

• Protease amylase and lipase are produced here. (If only there was a SMALL INTESTINE link)

Large Intestine

• Where excess water is absorbed from the food.

Anus

• Hehehehehe.

Right! The Enzymes:

Digestive enzymes break down the big molecules into the smaller ones. Like a squishy thing... um... a compactor!

Eco friendly Rubbish. Literally.

 Except it breaks down... not compacts... well... scrap that. See, scrap that? Like scrap metal? *sigh*

So learn these:

• Carbohydrases: Break down (digest) starch into sugars.
• Proteases: digest proteins into amino acids.
• Lipase: digests fat to fatty acids and glycerol.

Cell Organisation and the Circulatory System

Let's not over complicate, you need to know the 3 definitions. And that's a whole topic covered.

"A TISSUE is a group of similiar cells that work together to carry out a particular function"

"An ORGAN is a group of different tissues that work together to perform a particular function."

"An ORGAN SYSTEM is a group of organs working together to perform a particular function."

 The Circulatory System
4 chambers, one heart. Sounds like a romantic and yet sadistic sex film. And then four major blood vessels, not so sexual.

This is the order it works in:

1. Right atrium recieves deoxygenated blood from the body (through the VENA CAVA)
2. De-oxygenated blood moves through to the right ventricle which pumps it to the lungs.
3. The left atrium recieves the oxygenated blood (through the PULMONARY VEIN)
4. The oxygenated blood then moved through to the left ventricle and is pumped around the whole body.  (via the AORTA)

Or to put it in a shorter and simpler way:

De-oxygentated - vena cava - body - right ventricle - lungs - oxygenated blood - left atrium - left ventricle- aorta - whole body

Please don't sue me CGP...

A few important things to remember would be:

• 4 chambers in the heart
• 4 major blood vessels
• Left ventricle has a thicker wall that right ventricle
• Why? It pumps blood around the whole body so more force is needed due to more distance needed to be covered.
• VALVES prevent the backflow of blood.

Growth And Development

How do you measure growth in an animal or a plant?

Hahahahahaha.... No. Do you know how much that joke has been overused? No, don't measure it with a ruler.

"Growth is an increase in Size or Mass"

Learn that, should make it much simpler.

Measure it in 3 ways:

1. Size (length and width... Go on, make a penis joke)
2. Wet Mass (Organisms have loads of water, so why not measure it with it in?)
3. Dry Mass (Oh... I take that back. You can take it out and weigh it aswell.)

Why do things grow?

• Cell differentitation (the cell becomes specialised. Like a cell university degree)
• Cell Division (Say hi to Mitosis again! That's miTosis... Not meiosis.)
• Cell elongation (where a PLANT cell expands. PLANT CELL. PLANT.)

Evidence for Evolution

This one will be short and sweet, just like a girl I know... Ah, how nice eh.

• FOSSILS
• Caused by gradual replacement by minerals, this is basically teeth and stuff being replaced by minerals and becoming rock like substances.
• Impressions left by the body in rocks such as clay.
• Preservation in extreme environments were enzymes can't work to decay them.
• Fossil record is created by all the physical characteristics left behind in fossils to create a sort of timeline of the different fossils.
• There are big gaps in the fossil record due to very few plants and animals actually becoming fossils, and soft tissue does not turn into fossils. Unhelpful if you ask me. And some fossils have not been found yet.

THE PENTADACTYL LIMB

A pentadactyl limbs is a limb with 5 digits. Does your hand have five digits? If only there was a theory of evolution that explained that...

Obviously it was dead when this was taken...

Distribution of Organisms And Enviromental Factors

If you can remember primary school you probably already know this topic. But if, like me, you have the memory of a goldfish, then you might need some revising.

First things first:

Why?

Why bother collecting organisms? So you know where they live! That's about it to be honest...

The face things:

1. Pooters

These are little beakers with tubes and a gauze. You suck into a tube and the other tube, preferably the one without the gauze on, sucks the insect up. The gauze on your side stops you being bugged... Get it? I'm sorry.

    2.  Pitfall traps

It's a pit... they fall into... See the diagram:

    3. Sweep nets

A net with a strong cloth that is used to collect insects and spiders and stuff from long grass.

    4. Pond Nets

Used for collecting things from... ponds...

Quadrats

Bit more to remember on these! Basically all you need to know is count the organisms you see in your quadrat then do it again with somewhere else so the same ones don't sneak in. Then learn this:

"MEAN = TOTAL NUMBER OF ORGANISMS/ NUMBER OF QUADRATS

Enviromental Factors

You can do these things to measure them, all you need to know:

1. Use a thermometer to measure the temperature in different places
2. Use a light sensor for light intensity
3. Measure soil PH using indicator liquid. Acid soil? What next! 

Osmosis And Plant Stuff

Osmosis

"Osmosis is the movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration."

Well... that was easy... So if there's lots of it in one place, it goes to where there is less! Like a pimp.

The Ladies be flocking.

Active Transport

The process of root hairs absorbing minerals from the soil. ODD thing to remember. Active transport uses energy from respiration to help pull minerals into the root hairs. Confusing heh? Well, this is because it is normally a lower concentration of minerals in the soil compared to the root hairs. So would diffusion work? Of course not! Along comes active transport with it's cheeky respiration energy.

Cheeky Bugger...

Transpiration

Final bit on this! Simple definition:

"Transpiration is the Loss of Water from the plant"

The water loses it through the water evaporating from the leaves. The leaves are adapted for this due to stomata. Looks like they've been doing their homework... If you're here I guess you haven't.

Look! Even 4 year olds' understand it.

Photosynthesis

"The way that plants cook their tea."

With jokes like that I should work for CGP! If there's a job going... i'll take it.

The simple one is at the bottom. The arrow is photosynthesis. You learn that? Topic covered.




Well... Nearly.  You need to know a few things about photosynthesis! The leaves are adapted for mor efficient photosynthesis and there are a couple of things that slow photosynthesis down:

• LIGHT
• CO2
• TEMPERATURE

Bright, hot and gassy. Bit like the sun... hm... if only there was a link between the sun and photosynthesis. 

Meiosis: GCSE Biology Exam

SEX. SEX SEX SEX. Gametes.

There's a strong link between those words. Gametes are sex cells. If you cring at the the word sex, you probably want to be looking at the year 9 science bite size. Sorry.

Meiosis

This is the thing I struggle with the most. Got my book at the ready. Some key things to know before I begin fumbling through this topic:

• Meiosis produces four haploid nuclei. The chromosomes in these are not identical. I repeat, NOT IDENTICAL.
• Meiosis only happens in the reproductive organs like the testes and ovaries. If you don't know what the testes are, it's the 2 bits near your penis. If you don't know what a penis is... 
• Meiosis makes new cells that have half the original number of chromosomes.

I over complicate this all the time so i'll keep it simple.

If you didn't understand the diagram:

Maths terms: Doubles, halves and halves. (x2/2/2)

Ellie Griffin terms (thank god for her): If you make 6 cakes each for friends and have 4 friends you double the mixture to make 12 cakes, and then double them to make 24 and now you have enough! This backwards is simply divided by 4. 4 Haploid gametes.

Sorry this one is a bit crap... had to have Ellie explain it to me. Thank god for friends eh? 

Mitosis: GCSE Biology Exam

Mitosis and Meiosis (covered in another article) are key things to learn. I smell a possible six marker. Unlike someone I used to know... Oh yeah... you wont get that... He couldn't smell. MOVING ON. As with Biology it is a good idea to know definitions so get listening:

"Mitosis makes new cells for growth and repair."

There are lots of details unlikely to come up on the exam but a few things you might wanna know before I start rambling:

• Human body cells are diploid (2 versions of each chromosome, one from each parent)
• 23 pairs of chromosomes in in a human cell.

So:

Mitosis

Mitosis results in two identical cells. The cell gets the signal to duplicate the DNA in order to divide. The cells then have to go from being stringy things into pairs of arms to make chromosomes. In an x shape.

See? X shaped. Wasn't even lying this time.

WARNING: Although often depicted as different coloured arms of the chromosome the 2 arms of the chromosome are EXACT DUPLICATES.

Next comes the line-up. Like in the military and stuff. The chromosomes line up at the center of the cell and the cell fibres pull them apart. Not so much like the military. This is called the "Metaphase" but don't stress about that, not important!

The membranes form around the the new sets of chromosomes. These become the nuclei of the two cells. See where this is going?

Hehehehe... Cleavage.

Finally the cytoplasm divides! The chromomes return to their stringy origins within the new cells. There are now two new diploid cells with exactly the same DNA. This is called being "Genetically identical". Why? Because their genes are identical. Common sense people.

USEFUL FACT: Asexual reproduction uses Mitosis. You might get a question involving plant "runners". These plants use mitosis so when they produce new plants on the ends of these runners they will be genetically the same so are more likely to be the same size and have the same resistance to certain drugs as the original plant. Farmers often use this to breed larger plants by only killing smaller ones... Adds new meaning to the phrase "size matters" doesn't it? 

Protein Synthesis: GCSE Biology

Protein Synthesis is the hardest thing I've ever had to deal with... Well the second hardest. 1



Since it's difficult I thought I would try to format it a bit different. If not for you, so I can at least understand it.

Key Words: 

• Transcription
• Translation
• mRNA (Messenger RNA)
• RNA (Ribonucleic acid, a nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA)
• Codons (A triplet of bases)
• Ribosome (Or big Riby if you wish)
• tRNA 

First thing to remember PROTEINS ARE IMPORTANT. They are key in GROWTH AND BODY CHANGES. I will split this into the 2 stages:

Transcription:

2 DNA strands unzip. These are Complementary. This means the the strand is exactly the same. If it helps you to remember:

"Why, what a nice whip you have there! I also have the same model." 

This is a compliment and they have the same whip. Let's not go into details on that. Each to their own.

The mRNA molecule moves out of the nucleus and joins with a ribosome.

"I shall call him Riby and he shall be mine and he shall be my Riby. Come on, Riby Come on, little Riby."

The reason I put these crap jokes in is in hope that you might remember it in the exam and think oh I remember that guy trying to be funny with that stupid Riby joke... Riby... Ribosome! Boom, 1 more mark.

Anyhow, moving on. This brings us onto the following stage:

Translation

Amino acids are brought to big Riby by tRNA molecules. Why? Because the Ribosome is effectively a glue stick. It sticks the Amino Acids together in a chain to make a protein chain (polypeptide). "These follow the order of the triplet of bases called codons in the mRNA." A big sentence to simply say they are in 3s.

All of this ends up creating a protein that, due to the enzymes bringing the correct Amino acids, can do a certain job.

So if this confused you even more, i'll try and sum it up:

1. DNA Strands Unzip and complementary strand is created, this is mRNA. (TRANSCRIPTION) 
2. mRNA joins with Ribosome.
3. Amino acids specially selected by tRNA and brought to the Ribosome.
4. Ribosome sticks the amino acids together in codons. (TRANSLATION)

Well, I really hope this didn't confuse you more. Drop us a comment if it did and i'll answer best I can. 

1.The hardest thing was amalgamated algorithms, get your head out of the gutter.

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The Human Genome Project: GCSE Biology

My exam board says about the Human Genome project and needing to know the for points and the againsts. This will be a very short blog on it. As with all of my blogs it's mainly for my revision.

The "Human Genome Project" is a project to map all of the human genes. The idea is to collaborate all the scientists they could find to do this.

A simple way to remember the for and against points is to imagine this:

You are the manager of a company. You need to find a new security guard. This job requires, good eyesight, good hearing, strength and intelligence. You need to find the ideal candidate. This kind of job takes a lot of training to get used to the site they are guarding. Learn the door codes, learn the routines, learn the little hiding places for thieves. 

So this is where the human genome project becomes useful. Suddenly, judging from their past relatives, you can see one candidate is likely to get a heart disease later in life. Well, that's him out of the pile! 

Take it from the candidates perspective. No employer is going to employ someone likely to cost them money in sick pay. This is discrimination and is called "Gene-ism". It is a negative point of the Human Genome Project. 

However with this knowledge that you may get a heart disease later on in life means that doctors may be able to reduce the chances of this by informing you of diet changes and lifestyle changes that could save or at least prolong your life. This is "Preventing and Predicting Diseases" and is a positive point of the Human Genome Project.

Knowing what diseases someone may get can be very useful for "Accurate Diagnoses". This is a good point of the Human Genome Project. 

A sort of sci-fi point of the Human Genome Project is that in the future we could determine what a thief looks like from DNA samples. This would "Improve Forensic Science" and is a good point of the Human Genome Project. 

Some insects climb into peoples skin and lay eggs that hatch and then the baby insects slowly eat your skin. Maybe they're on you now... Paranoid? You should be. If you knew you were likely to get a skin disease or a heart condition you would spend your entire life worrying about it every time you looked in the mirror or had a pain in your chest. This is called "Increased Stress" and is a bad point of the Human Genome Project.

I have repeated the name "Human Genome Project" a million times. So DON'T FORGET IT. The red paragraphs are negative and the green positive points about it. What's it? The Human Genome Project. 

Hope it comes up in the exam and it's an easy 4 marks for you. Maybe 6, you could be lucky.

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