1
Q
What are the two stages of cell division?
A
- nuclear division - the nuclear divides (eg. mitosis, meiosis)
- cytokinesis - the whole cell divides
2
Q
What must be done before the nucleus divides?
A
DNA replication
3
Q
What is the model called that shows how DNA replicates?
A
Semi-conservative model
4
Q
What is the enzyme called that breaks hydrogen bonds between bases?
A
DNA helicase
5
Q
What is the enzyme called that joins free nucleotides together?
A
DNA polymerase
6
Q
What are the stages of semi-conservative replication?
A
- DNA helicase (enzyme) breaks the hydrogen bonds that link the bases together
- the double helix separates into two strands
- each exposed polynucleotide strand acts as a template as free nucleotides attract to their complementary bases
- DNA polymerase (enzyme) join the free nucleotides together in condensation reaction
- each copy of DNA is made up of one original DNA strand and one new DNA strand
7
Q
What is the function of DNA helicase?
A
Breaking hydrogen bonds that link the bases together
8
Q
What is the function of DNA polymerase?
A
Joining free nucleotides together by condensation
A-Level AQA Biology
flashcards
Decks in class (62)
# Cards
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1.1 Introduction to Biological Molecules7
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1.2 Carbohydrates — monosaccharides10
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1.3 Carbohydrates — disaccharides and polysaccharides13
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1.4 Starch, glycogen and cellulose17
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1.5 Lipids17
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1.6 Proteins27
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1.7 Enzyme action7
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1.8 Factors affecting enzyme actions13
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1.9 Enzyme inhibition9
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2.1 Structure of RNA and DNA27
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2.2 DNA replication8
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2.3 Energy and ATP16
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2.4 Water and its functions16
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(2.5 Inorganic ions)13
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3.1 Methods of studying cells22
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3.2 The electron microscope7
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3.3 Microscope measurements and calculations3
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3.4 Eukaryotic cell structure51
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3.5 Cell specialisation and organisation11
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3.6 Prokaryotic cells and viruses19
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3.7 Mitosis17
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3.8 The cell cycle6
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4.1 Structure of the cell-surface membrane23
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4.2 Diffusion7
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4.3 Osmosis21
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4.4 Active transport6
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4.5 Co-transport and absorption of glucose in the ileum6
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5.1 Defence mechanisms14
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5.2 Phagocytosis7
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5.3 T lymphocytes and cell-mediated immunity9
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5.4 B lymphocytes and humoral immunity9
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5.5 Antibodies13
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5.6 Vaccination6
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5.7 The human immunideficiency virus (HIV)0
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6.1 Exchange between organisms and their environment0
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6.2 Gas exchange in single-celled organisms and insects0
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6.3 Gas exchange in fish0
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6.4 Gas exchange in the leaf of a plant0
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6.5 Limiting water loss0
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6.6 Structure of the human gas-exchange system0
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6.7 The mechanism of breathing0
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6.8 Exchange of gases in the lungs0
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6.9 Enzymes and digestion0
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6.10 Absorption of the products of digestion0
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7.1 Haemoglobin0
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7.2 Transport of oxygen by haemoglobin0
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7.3 Circulatory system of a mammal0
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7.4 The structure of the heart0
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7.5 The cardiac cycle0
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7.6 Blood vessels and their functions0
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7.7 Transport of water in the xylem0
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7.8 Transport of organic substances in the phloem0
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7.9 Investigating transport in plants0
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8.1 Gene and the genetic code16
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8.2 DNA and chromosomes7
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8.3 Structures of ribonucleic acid13
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8.4 Polypeptide synthesis - transcription and splicing14
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8.5 Polypeptide synthesis - translation3
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9.1 Gene mutation16
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9.2 Meiosis and genetic variation4
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9.3 Genetic diversity and adaptation0
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9.4 Types of selection0
