Biology - Specification Guide for learning outcomes

https://filestore.aqa.org.uk/resources/biology/specifications/AQA-8461-SP-2016.PDF

Do Now: Bio Topic 2- Cell Organisation

Tissue Adaptation Function

epidermal tissue (upper)

palisade mesophyll

spongy mesophyll

epidermal tissue (lower)

vascular bundles

Support: Complete the table below to help you answer:

Starter Task: Describe how a leaf is adapted for photosynthesis.(6 marks)

Check and correct:

Mark Scheme:

Any three from:• Epidermal layer which covers the leaf: transparent so light can

penetrate the leaf.• Palisade layer: contains chloroplast to trap light during

photosynthesis. It is near the top of the leaf so gets more sunlight.• Spongy mesophyll: has spaces/pockets for gas exchange.• Xylem: transports water around the plant.• Phloem: transports sugars around the plant.• Stomata/guard cells: allow gases into and out of the leaf, also

controlling the amount of water lost.

Sample Exam Questions:

What are the adaptations of the red blood cells? (3 marks)• No nucleus so can carry more oxygen. • Haemoglobin to bind the oxygen. • A large surface area to absorb more oxygen.

Why is it a problem if someone does not have any platelets? (3 marks) • Their blood will not clot when they get a wound. • More risk of infection. • They risk losing a lot of blood.

In your books, answer these questions about types of blood cell

Carries oxygen to tissues

Biconcave

So they can fit in more oxygen

So they can fit in more oxygen

Binds to oxygen

Carries dissolved substances such as CO2, antibodies, hormones. Transfers heat in the body. Suspends and carries blood cells

Destroys pathogens in the blood

Antibodies and antitoxins

To help destroy pathogens

White blood cells do not have a nucleus

Clot blood at the site of a wound

They can bleed uncontrollably

Read: Enzymes in DigestionWhy have enzymes in digestion?

To break down larger chains into smaller moleculesso they can be absorbed into the blood stream.

There are 3 types of enzymes in digestion:

• protease;

• amylase;

• lipase.

Carbohydrase

Carbohydrase breaks down carbohydrates into smaller sugar molecules. It is produced in the salivary glands and the pancreas. Amylase (an example of a carbohydrase) will breakdown starch in themouth and in the small intestine.

Carbohydrase

Starch moleculeSugar molecules

Digestion

Protease

Protease breaks down protein into smaller amino acid molecules.

Protease will breakdown protein in the stomach and in the small intestine.

Protein molecule Amino acid molecules

Digestion

LipaseLipase breaks down lipids into fatty acids and glycerol molecules.

Digestion of fat occurs in the small intestine.

Fat molecules Fatty acid molecules and Glycerol molecules

Lipase

Task: Fill in the blanks using the diagram below

• Enzymes are , they increase the rates of a chemical reaction without being used up. They are made of and are involved in reactions such as and photosynthesis.

• They have an where the reaction occurs. The enters the active site and the eventually leaves the active site.

• Enzymes work like a and they are specific to a reaction.

Substrate enteringactive site of enzyme

Enzyme/substratecomplex

Products leavingactive site of enzyme

ProductsEnzyme changes shape slightly as substrate binds

Active site

Substrate Challenge: Make a list of key words as you are answering the above

Check and correct:

• Enzymes are biological catalysts, they increase the rates of a chemical reaction without being used up. They are made of proteins and are involved in reactions such as respiration and photosynthesis.

• They have an active site where the reaction occurs. The substrateenters the active site and the product eventually leaves the active site.

• Enzymes work like a lock and key – they are specific to a reaction.

Task: Describe the graphs below, using your knowledge on enzymes

1) 2)

Answers: Describe the graphs below

As the temperature increases so does the rate of reaction, until it reaches the optimum, when it then becomes too hot and the rate of reaction decreases. The enzymes become denatured.

As the pH increases so does the rate of reaction, until it reaches the optimum, when the pH becomes to high and the rate of reaction decreases. The enzymes become denatured.

Exam Question:

In coronary heart disease (CHD) layers of fatty material build up inside the coronary arteries. This can cause a heart attack.Statins and stents can be used to reduce the risk of a heart attack in people with CHD.

Evaluate the use of statins and stents in people with CHD.

Remember to include a justified conclusion. [6 marks]

AQA mark allocation template:

Mark Scheme:

pros of statins:• decreases blood cholesterol • slows down build-up of fatty material in arteries • (so) blood can flow to heart muscle cellscons of statins:• drug has to be taken regularly or may forget to take drug• drug will need to be taken long-term • side-effects of taking the drug • effects of drug will take time to happe

pros of stents:•blocked artery is held open • (so) blood can flow to heart muscle cells• will remain in place / work for a long time• rapid recovery timecons of stents:• risk of infection from procedure • risk of surgery eg heart attack• risk of thrombosis or blood clot

• a justified conclusion