Year 11 Biology Notes for GCSE Triple Science

B7 Skeletal System

Why do we have a skeletal system?

• Maintains the stability and structure of your body 
• Stores minerals such as calcium and phosphorous 
• Makes red blood cells, platelets and some white blood cells in the bone marrow
• Forms a system of levers with muscles attached your body to move
• Protects internal organs, e.g: ribcage as it protects the heart 

Vertebrate Skeletons

Whale: 

• Similarities: ribcage and skull
• Differences: fins
• How Suited: fins to power through the water

Rabbit: 

• Similarities: ribcage and skull
• Differences: short bent legs
• How Suited: short bent legs to hop, adapted to move using back legs/bones 

Frog: 

• Similarities: skull
• Differences: small, eat a lot
• How Suited: small to make it’s way through and bones are adapted

Bird:

• Similarities: ribcage and skull
• Differences: wings
• How Suited: wings to glide, through the air without falling 

Bones in the human body do not look the same, because they are used for different purposes. The jaw bone and wrist bones look different and act completely different. The jaw bone has to be the shape it is for moving when eating and to protect the teeth whereas the wrist bone are going to the phalanges 

Lets Get Fit!

Medical:

• Genetic diseases
• Medication 
• Allergies 
• Family medical history 
• Surgery 

Lifestyle:

• Smoking 
• Food choices
• Alcohol consumption 
• Drug consumption 
• Healthy or active 

• Heart rate will be less
• Blood pressure will be lower 
• Recovery period will be shorter
• Proportion of body fat will be smaller 
• Body mass index will be smaller 

Injuries 

Injuries which we can gain from exercise:

• Tear muscle 
• Sprain 
• Break bones
• Dislocation 
• Wear away cartilage 
• Tear ligaments 

Description and Symptoms of an Injury

Sprain:

Most common sporting injury, it can happen when you overstretch by twisting you ankle or knee 

Redness, swelling and bruising around the area makes it difficult walking. Sharp pain when pressure is applied 

Torn ligament and Tendon:

If a joint is overstretched then the ligaments or tendon can tear. 

Bruising and hard to bend, see a physiotherapist

Dislocation:

When part of a bone steps out of the joint

Rugby shoulder dislocation are very common

Bruises occur when swollen 

Rest - immobilise injury

Ice - to reduce swelling, slows down flow of blood to the injured area

Compression - wrap bandage round to reduce blood 

Elevation - raise injured area above the heart to also reduce blood flow 

Simple stretching routines - when swelling stops to gain mobility 

Aerobic exercise - does not start until 75%of the previous level of strength of the injured area has been regained, helps to return the athlete to peak fitness

If a person does not follow the treatment regime their joint does not heal property, stiff and painful and likely to injure again as it is weaker 

Physiotherapists often produce a treatment regime specifically designed to heal a persons injury. Normally they give gentle exercise to start with to ensure the tissues to heal well and progress 

1. The role of a physiotherapist is to help a person who has or injure to make it better, and make a joint stronger so the injury will not occur again 

The Double Pump

White blood cells produce antibodies 

Red blood cells carry oxygen 

Platelets (forms scabs) to stop bleeding 

Plasma is a liquid which makes everything move 

Blood Component	Apperance	Function	What happens if this part of the blood is lost or defective
Red Blood Cells	round, looks like a donut without a hole, Bio- concave with no nucleus	gives blood its colour, 40-48% of blood carries oxygen	Wont get oxygen, muscle wont work and will die
Platelets	Small, starship, stick to each other	Plug holes in vessels, stop blood in 5 mins	Carry on bleeding, and will bleed to death
White Body Cells	white, big, round shape	Fights diseases and viruses	No fight for the viruses, will die eventually
Plasma	yellow liquid, sugar	Carry cells in blood	Cells wont reach other cells, will die

Vein and Tissue Fluid

Artery:

• Thick walls to withstand pressure
• Carries blood away from the heart

Capillary:

• 1 cell thick 

Vein:

• Thin walls as not under pressure 
• takes blood to the heart 
• valves to stop the heart back flow

Sensing and Controlling 

Hypothalamus:

• Process is automatic and without any conscious thought 
• If the temperature of body is not right, brings effect in, putting body temperature back to normal 
• There are temperature receptors 
• Processing centre is in the brain 
• Cerebral hemisphere - where you make conscious choices if you are hot or cold

  

	Too Hot	Too Cold
Conscious Action	Drink cool water, take clothes off, open windows	Hot bath, turn heating on,
Unconscious Action	Sweating, arms hair lie down	Shivering, arms hair stand up

Too Cold	Too Hot
Muscles shiver - energy warms the body tissue as muscles contract when you shiver	Muscles relax
No sweat made	Sweat is made
Hairs raised - erector muscles make your hair stand on end, trapping a layer of warm air	Hairs lie down - do not trap warm air
Skin goes paler - blood is diverted away from the skin surface to the core to retain warmth	Skin goes red
Warming behaviours - do exercise to warm up, put on more clothes or having a warm drink	Cooling behaviours - take clothes off, have cool drink

Controlling our Temperature 

Temperature control is an antagonistic behaviour, when two receptors are the opposite effect but can control your temperature, when you are cold you start shivering and you have pale skin, your muscles contact to move blood around the body to warm up the skin or when you are too hot muscles relax. 

Thermoregulation is the control of a constant internal body temperature, by antagonistic behaviour. Antagonistic behaviour is where there are two receptors for one change by muscles. So when body temperature is to high, vasodilation is when temperature receptors detect a rise in temperature and send a message to the hypothalamus. The hypothalamus stops sending nerve impulses to muscles in blood vessel walls. The muscles in blood vessel walls relax, so the blood vessels near the skin dilate, increasing the amount of heat loss. Vasoconstriction detect a fall in temperature and sends a message to the hypothalamus. The hypothalamus sends nerve impulses to muscles in blood vessel wall, causing the muscles to contract, constricting the blood vessels near the skin reducing the amount of heat loss. Overall, vasodilation is when your body gets too hot and blood vessels dilate increasing heat loss and vasoconstriction is when your body gets to cold and blood vessels constrict reducing heat loss 

Controlling Sugar Levels 

• Processed foods have a high sugar content 
• Insulin is a hormone, breaks down glucose and remove it from the blood 
• Energy boost received from sugar quickly falls and experiences a sugar low 
• Complex carbohydrates such as rice/pasta have a slow release of sugar, keeping your blood sugar level balanced 

Pancreases is the organ responsible for making insulin. When detecting a low sugar level it stops making insulin

1. Processed foods which are high in sugar: chicken nuggets, crisps, fast food, white, rice, fizzy drinks, sugary cereals, canned fruit and processes meats
2. Foods which are high in fibre and complex carbohydrates: oatmeal, brown rice, whole-grain breads, pastas, potatoes, beans, peas and lentils 
3. Top 5 items with more than 15g of sugar per 100g:

• Fruit Cake - 43.1g
• Plain Chocolate - 52.1g
• Honey - 81.1g 
• Cornflakes (sugar coated) - 39.6g
• Puffed Wheat (sugar & honey coated) - 57.4g

4.Top 5 items with highest amount of sugar per portion 

• Milkshake - 52.8g
• Dried Apricots - 50.6g
• Fruit Cake - 48.7g
• Cola - 39.2g
• Strawberry Yogurt - 34.7g

5. A man could drink 6 milkshakes in a day and stay below the guideline and having 5g left over

Coursework

For a reaction to occur the reactants must collide with enough energy to produce a reaction. An enzyme acts as catalyst by reducing the amount of energy needed for the reaction to occur. This cause the rate of reaction to increase. 

Each enzyme has a different shape, within the shape is the active zone, only one type of substrate fits into the active site, once the substrate is attached to the active site it is turned into the products 

Enzymes 

A catalyst is a chemical that speeds up a reaction but is not changed or used up

Enzymes are proteins made up - long chains of amino acids. They are biological catalysts which speed up chemical reactions 

They increase the rate of reactions - photosynthesis, respiration, digestion, protein synthesis 

Each enzyme is specific to a substrate, substrates are changed into products 

Denaturing enzymes: If the shape of enzyme changes, the substrate cannot fit into the active site 

Two factors which cause it to happen:

1. Temperature
2. PH Level 

Milk + Lipase → Fatty Acids + Glycerol 

How?

Temperature 

As temperature increases, so does the rate of reaction. But only up to a certain point as the enzyme becomes denatured at too high temperatures

At 32.C the enzyme works at it’s optimum 

PH Level

Different enzymes work best at different PH values. The optimum PH value depends on the enzyme and where it works. This enzyme optimum is PH 8. Enzymes will become denatured at PH values too far from their optimum 

The effect of temperature on lipase

Milk contains fats and sugar/starch 

These are broken down by lipase to make fatty acids 

Introduction:

• Background science
• What are enzymes 
• Uses and advantages of enzymes
• How they work
• Lock and Key
• Activation Energy 
• Factors that affect the rate of reaction: concentration, PH, Temperature, Enzyme inhibitors 

Equipment Introduction 

Measuring Volume Equipment:

A systematic error is an error that naturally occurs. You must recognise systemic errors and minimise error when measuring solutions, you should measure to the bottom of meniscus at eye level. 

Burette:

• Graduated in divisions of 0.1cm3 
• Maximum error is half a division 
• Hard to measure small amounts 

Syringes - 5ml, 10ml 25ml, 60ml

PH test - may have to use a pipette 

Pipette is not prices as the drops may not be the same amount every time 

Mixing Volume Equipment:

Mixing thermometer - can take the temperature and stir at the same time whereas a glass rod is not good because it only stirs. 

Boiling Tube/ Test tube: 

a boiling tube is better to use in the temperature experiment because there is a larger surface areas so the temperature is more easily spread and makes mixing easy 

A test tube is better to use in the PH level experience and so is using a conical flask 

Timing equipment - you get greater precision with digital than analogue 

Reactants:

Diastase rather than analyse 

Full fat milk rather than skimmed milk - more fat for lipase to break down 

On the PH test, I need to put iodine onto a spotted line as it keeps solutions separate  

PH Preluim: Diastase Activity  

Method:

• Drop iodine onto all 3 spotting tiles 
• Have test tubes to put into a test tube rack 
• Add 1ml of PH solution to a test tube and 2ml of diastase 
• Adding 5ml of starch to the test tube with the ph and the enzyme solution
• Start the stopwatch until completely dissolved
• Every 10  seconds (interval) add one/two drops of the solution to the spotting tile, until the iodine is no longer showing that starch is present in the reaction mixture 
• Count the amount of tiles (1 tile= 10 seconds)
• Repeat this experiment for the other PH’s
• How many repeats of each PH will I do?
• Justify why I did the steps 

The Affect of Temperature on the Enzyme Lipase:

• Use five different temperatures
• Use boiling tubes instead of test tubes because boiling tubes have a larger surface areas and easier to stir
• Label the boiling tubes to the temperature you are testing and intervals 
• Add five drops of phenolphthalein to each boiling tube, also need a controlled tube (adding 5ml of full fat milk and 7ml of boiling water)
• Measure out 5ml of full fat milk using a 5ml syringe 
• Add the milk to the boiling tube which contains the phenolphthalein 
• Using a 10ml syringe to measure out 7ml of sodium carbonate solution 
• Then add it to the phenolphthalein and full fat milk to each boiling tube 
• After adding a thermometer, shake the lipase solution
• Get 5 different 100ml beakers - measure 10ml of the lipase
• Place into the water bath of the temperature you are wanting the lipase, controlled boiling tube and the solution to be at 
• Using a 2ml syringe (or 2.5ml), measure out 1ml of lipase
• Adding the lipase to the solution and start the stopwatch, until the boiling tube turns back to the controlled boiling tube, time how long this takes to occur. 
• Overall, repeat it 3 times for each of the five temperatures 

Final Experiment

Method:

I am going to measure five different temperatures three times so I can get accurate and reliable results . 

Temperatures:

30.C, 40.C, 50.C, 60.C

Step One: Add five drops of phenolphthalein using the 1ml syringe in each boiling tube. Label them with initials and the temperature, so you can clearly see what ones are yours and will not mix up the results 

Step Two: Measure out 5ml of full fat milk by using a 5ml syringe. Then add that to the boiling tube containing the phenolphthalein

Step Three: Use a 10ml syringe to measure out 7ml of sodium carbonate. Then add it to the phenolphthalein and full fat milk tube 

Step Four: Add a thermometer to each boiling tube

Step Five: Shaking the lipase solution - otherwise the lipase would be at the bottom 

Step Six: Using a 2.5ml syringe twice to get 5ml of lipase - You can not using a 5/10ml syringe because it will not fit into the bottle 

Step Seven: Add the lipase to the boiling tube and start the stopwatch until it looks like the the controlled tube. Write down how long it took  

Results Table:

Temperature	Time Taken for Reaction
30.C	5 minutes
40.C	3 minutes 11 seconds
50.C	4 minutes 2 seconds
60.C	10 minutes - incomplete

Risk Assessment: 

Enzyme 

Potential allergens, they can cause asthma and/or irritate the membrane of the eyes and nose 

If swallowed - wash out the mouth and give a glass of water. Seek medical attention 

In eyes - flood the eye with water for 10 minutes

Split of skin and clothes - remove contaminated clothing, flood the area with water, wash self thoroughly with soap and cold water 

Justification of Method:

• Same person measuring out - reduces human error 
• Repeat 5 times - increase of confidence in results 
• Same person timing - reduces human error 
• Remove outliers - accurate average calculated 
• Using a syringe - more accurate than a pipette