Biology Unit 2 Revision

Questions and answers from past papers

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  • Created by: bethedoc
  • Created on: 03-04-13 12:56
Describe the function of a chloroplast.
Absorbs light for photosynthesis and to produce carbohydrates/sugars/lipids/protein
1 of 16
Describe what happens during anaphase.
Identical chromatids are pulled by spindle fibres to opposite poles
2 of 16
Explain why some cells will have 8.4 units of DNA and others will have 4.2.
8.4 cells have replicated DNA and are in late interphase. 4.2 = DNA has not replicated - early interphase of cell has just divided
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Give 2 ways in which courtship increases the probability of successful mating.
1. Attracts same species. 2. attracts opposite sex. 3. Indication of fertility. 4. Stimulates release of gametes
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Explain how mutation leads to the formation of non-functioning DNA.
1.Change in amino acid sequence 2.Change in hydrogen bonds 3.Alter tertiary structure of enzyme 4. Substrate not complimentary
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Suggest how the spread of mutation may have occured.
Founder effect / interbreeding
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Frequent treatment of bacteria can result in resistant strains. Explain how.
1. Mutation occurs 2. Resistant gene/allele 3.Resistant bacteria survive and reproduce 4.Vertical transmission through conjunction
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Explain how a gene is passed from one species of bacterium to another.
1. Horizontal gene transmission 2.via conjugation 3.plasmid/gene is replicated 4. plasmid transferred
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Scientists use protein structure to investigate the evolutionary relationships between species. Explain how.
1. Amino acid sequence 2.closer the amino acid sequence the closer the relationship 3.protein structure related to triplet sequence
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Comparing the base sequences of genes provides more evolutionary information that comparing structure of proteins. Explain why.
1. more bases than amino acids 2. Introns/non-coding DNA 3. Degeneracy of code/ more than one code for each amino acid
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Explain the importance of using a large sample size.
Produces a more reliable mean/ identify anomalies
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Explain the importance of taking random samples.
Removes bias
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Describe what causes root pressure.
1. Active transport by endodermis 2. Ions/salts into xylem 3. lowers water potential in xylem 4. water enters by osmosis
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Explain how oxygen is loaded, transported and unloaded in the blood.
1. haemoglobin carries oxygen 2. in red blood cells 3. loading in the lungs 4. at high partial pressure of oxygen 5. unloads to respiring cells/ tissues 6. at low partial pressure of oxygen 7. unloading linked to higher carbon dioxide concentration
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Suggest factors that should be considered when selecting volunteers for trials.
1. Age 2. sex 3. lifestyle 4. health 5. genetic factors 6. ethnicity
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Give 2 features to improve the reliability of results.
1. large sample number 2. different (countries)
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Other cards in this set

Card 2

Front

Describe what happens during anaphase.

Back

Identical chromatids are pulled by spindle fibres to opposite poles

Card 3

Front

Explain why some cells will have 8.4 units of DNA and others will have 4.2.

Back

Preview of the front of card 3

Card 4

Front

Give 2 ways in which courtship increases the probability of successful mating.

Back

Preview of the front of card 4

Card 5

Front

Explain how mutation leads to the formation of non-functioning DNA.

Back

Preview of the front of card 5
View more cards

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