B3 flash cards OCR higher

Biology OCR gateway, b3, higher 2011 +

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Why do liver and muscle cells have large numbers of mitochondria?
Respiration occurs in mitochondria. The liver carries out many functions and muscle cells need to contract. Therefore they both need lots of energy.
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What's the position and function of ribosomes in a cell?
They're found in the cytoplasm, they're the site of protein synthesis.
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What's the shape of a DNA molecule?
Made from 2 strands coiled to form a double helix. Pairs of bases hold the strands together by forming cross links.
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How do bases code DNA for proteins?
DNA base code controls which protein is made. The base sequence in the DnA codes for amino acid sequence in the protein. Each amino acid is coded for by a sequence of 3 bases
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Why are enzymes specific?
Each enzyme has a different shape because of it's unique sequence of amino acids. Only one type of substrate can fit into the active site making an enzyme specific to a reaction.
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How can changes to genes alter proteins?
If there's a mutation the protein can change shape meaning it can no longer do it's job in the cell
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How can changing temperature affect enzyme action?
If the temperature is too high or low the enzyme will denature, the substrate can't fit so the reaction is slower.
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Whats the symbol equation for aerobic respiration?
C H O + 6CO --> 6CO + 6H 0
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What's collagen?
Protein can be found in the walls of arteries... makes walls stronger
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What's insulin?
Hormone used to control blood sugar levels.
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What's haemoglobin?
Used to carry oxygen around the body.
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What increases the risk of mutations?
Radiation and chemical exposure e.g in cigarettes.
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The lock and key?
Part of an enzyme is called the active site, the substrate molecules fit into the active site when a reaction takes place.
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What do enzymes do to chemical reactions?
Enzymes speed up particular reactions
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What is the role of ATP cells?
Respiration releases energy, which is then stored in ATP molecules. ATP molecule is used as an energy source for many processes inside the cell.
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What's the word equation for lactic acid?
Glucose--> lactic acid
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Why does anaerobin respiration happen during exercise?
Because the muscles don't recieve sufficient oxygen.
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What's oxygen debt?
The incomplete break down of glucose resulting in the build up of lactic acid.
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What are advantages of being multicellular?
Allows an organism to become larger and more complex. It also allows different cells to take on different jobs. CELL DIFFERENTIATION.
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What's DNA replication?
The two strands of the DNA molecule 'unzipping' to form single strands. New double strands forming by DNA bases lining up in complementary pairings.
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How does mitosis occur?
Chromosomes line up along the centre of the cell and divide. Then copies move to opposite poles of the cell.
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How is a sperm cell adapted to it's function?
Many mitochondria to provide energy for swimming to the egg. An acrosome that releases enzymes to digest the egg membrane.
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How's a red blood cell adapted to it's function?
Small- can pass through small blood vessels. Shaped like biconcave disks- large surface area to exchange oxygen quicker. Contain haemoglobin- to combine with oxygen. No nucleus- more haemoglobin can fit in.
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How are arteries adapted to their function?
Thick muscular and elastic wall to resist high pressure.
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How are veins adapted to their function?
Large lumen and valves to try and keep blood moving back to the heart because pressure is low.
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How are capillaries adapted to their function?
Permeable walls so substances can be transferred between blood and the tissues.
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What's the difference between bacterial cells and animal cells?
Bacterial cells dont have a nucleus, mitochondria or chloroplasts.
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What are some advantages and disadvantages of different types of growth?
Dry mass- measures growth but organism must be killed. Wet mass- hard for some organisms e.g trees, easy for animals. Water content in an animal can vary at any time.
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What are stem cells?
Cells which stay undifferentiated. They can develop into different types of cells.
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What's the difference between adult and embryonic stem cells?
Embryonic stem cells can form a greater range of cell types and are easier to find.
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What are the problems with using stem cells?
Some people argue that it's ethically wrong.
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What are some consequences of inbreeding?
Can reduce the gene pool, which can then lead to an increased risk of harmful recessive characteristics and reduction in variation.
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What are some benefits and risks of genetic engineering?
Advantage- production of organisms with the desired features quickly. Disadvantage- inserted genes may have unexpected and harmful side effects.
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What are the main stages in genetic engineering?
1- Desired characteristics selected. 2-Genes identified and removed. 3- Genes inserted into other organisms. 4- Organisms allowed to reproduce.
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What are some possible used of cloning?
Mass producing animals with desirable characteristics. Producing animals that have been genetically engineers to provide human products e.g insulin. Producing human embryos to supply stem cells for therapy.
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What are the main steps of cloning?
1- remove the nucleus from the egg cell 2- put nucleus from an udder cell into the egg cell. 3- give the egg cell and electric shock to cause division 4- implant embryo into a surrogate mother.
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How are plants cloned?
1- Plant with desired characteristics 2- Remove large number of small pieces of plant tissue 3- using aseptic technique- keep everything sterile 4- using suitable growth conditions.
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Why's cloning plants easier than cloning animals?
Plant cells retain the ability to differentiate. Animals lose this ability from an early age.
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Other cards in this set

Card 2

Front

What's the position and function of ribosomes in a cell?

Back

They're found in the cytoplasm, they're the site of protein synthesis.

Card 3

Front

What's the shape of a DNA molecule?

Back

Preview of the front of card 3

Card 4

Front

How do bases code DNA for proteins?

Back

Preview of the front of card 4

Card 5

Front

Why are enzymes specific?

Back

Preview of the front of card 5
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Comments

ruby

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Very good but some errors made in the formula's

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