Biology Unit 2b Revision

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What are enzymes?
Biological Catalysts
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What does Amylase breakdown?
Starch -> Glucose
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What does Protease breakdown?
Protein -> Amino Acids
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What does Lipase breakdown?
Lipid -> Fatty Acids & Glycerol
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What is the different between fats and oils
Fats = solids at room temp / Oils = liquids at room temp
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What does ....ase on the end of a word mean?
That it is an enzyme
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Where is amylase produced?
Salivary glands/Pancreas/Small Intestine
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Where is protease produced?
Stomach/Pancreas/Small Intestine
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Where is lipase produced?
Pancreas/Small Intestine
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What acid is produced in the stomach?
HCl which makes the stomch conditions the right pH for the protease enzyme to work
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Why is bile produced by the liver?
Bile is alkaline and it neutralises the acid -> breaks down the fat into tiny droplets (emulsifies fats) meaning that the bigger surface area for lipase to work on
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What effect has temperature on the enzymes?
If it gets too hot the enzymes denature and change shape so that they are no longer useful because they don't fit the substrate anymore.
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What effect has pH on the enzymes?
If the pH is too high or too low th pH makes the enzyme denaturise
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Why is Protease used in baby food?
It's used in baby food because protease pre-digests the proteins
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Why is protease and lipase used in biological detergents?
Protease breaks down any protein stains and lipase breaks down fat stains. They work best at 37^0C
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What would amylase do to potato skins?
It would break them down into glucose (sugar)
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How is fructose made?
When isomerase is added to glucose to make a sweeter sugar (fructose)
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What are proteins made up of?
Long chains of amino acids
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What do proteins act as?
Structural components of tissues such as muscles, Hormones, Antibodies, Catalysts
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What are the chemical reactions that occur during aerobic respiration (uses oxygen)?
Use glucose and oxygen. Release energy
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Where do most of the reactions in aerobic respiration take place?
Inside the mitochondria
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What is the equation of aerobic respiration?
Glucose + Oxygen -> Carbon dioxide + water (+energy)
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How might the energy released during respiration be used?
To build larger molecules from smaller ones, In animals to enable muscles to contract, In mammals and birds to maintain a steady body temperature in colder surroundings. In plants to build up sugars, nitrates and other nutrients into amino acids
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During exercise the blood flow to the muscles increases, what does this mean?
increases the supply of sugar and oxygen and increases the rate of removal of carbon dioxide
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What do muscles store glucose as?
Glycogen, which the muscles then covert back into glucose during exercise
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What is anaerobic respiration?
The incomplete breakdown of glucose and produces lactic acid
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Why is there less energy produced in anaerobic respiration than in aerobic respiration?
The breakdown of glucose is incomplete. It results in oxygen debt that has to be repaid in order to oxidise lactic acid carbon dioxide and water
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What is a cause of muscle fatigue?
The build-up of lactic acid in the muscles. Blood flowing through the muscles removed the lactic acid
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What do chromosomes contain?
Genetic information (DNA)
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What happens when a body cell divides by mitosis?
Copies of genetic material are made, then the cell divides once to form 2 genetically identical body cells
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When may mitosis occur?
During growth or to produce replacement cells
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How are gametes different to Body cells?
Body cells have 2 sets of chromosomes where as gametes only have one
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What is it called when the cell divides to form gametes
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What happens when a cell divides to form gametes?
Copies of the genetic information are made and then the cell divides twice to form 4 gametes, each with a single set of chromosomes
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What happens when gametes join at fertilisation?
A single body cell with new pairs of chromosomes is formed, a new individual then develops by this cell repeatedly dividing by mitosis
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Why does sexual reproduction cause genetic variation?
When gametes fuse, one of each pair of alleles comes from each parent
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Is it a male of a female if the chromosomes are the same (XX)?
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What is a dominant allele?
An allele that controls the development of a characteristic when it is present on only one of the chromosomes
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What is a recessive allele?
An allele that controls the development of characteristics only if the dominant allele is not present
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What is a gene?
Small section of DNA
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What is polydactyly?
Having extra fingers or toes. It's caused by a dominant allele of a gene and can therefor be passed on by only one parent who was the disorder
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What is Cystic Fibrosis?
A disorder of the cell membranes. This must be inherited from both parents. The parents may be carriers of the disorder without actually having the disorder themselves. It's caused by a recessive allele of a gene.
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Where does evidence of early forms of life come from?
Fossils va
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What are fossils?
Are the remains of organisms from many years ago which are found in rock.
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How can fossils be formed?
From the hard parts of animals that do not decay easily. From parts of organisms that have not decayed because one or more of the conditions needs for decay are absent. When parts of the organism are replaced by other materials as they decay.
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How might extinction be caused?
Changes to the environment over geological time, New predators, New diseases, New/more successful competitors, A single catastrophic event, Through the cyclical nature of speciation
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How may new species arise?
Isolation - 2 populations of a species become separated. Genetic Variation, Natural Selection and Speciation
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How do new species arise from Genetic Variation, Natural Selection
Genetic Variation - Each pop has a wide range of alleles that control their characteristics. Natural Selection - In each pop the alleles that control the characteristics which help the organism to survive are selected.
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How does speciation mean that new species have arised?
The populations becomes so different that successful interbreeding is no longer possible
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Card 2


What does Amylase breakdown?


Starch -> Glucose

Card 3


What does Protease breakdown?


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Card 4


What does Lipase breakdown?


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Card 5


What is the different between fats and oils


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