Dna And Genetics

Front 1

A DNA nucleotide consists of what?

Back 1

A deoxyribose sugar, a phosphate group and a base

Front 2

Which bases are purines

Back 2

Adenine and guanine

Front 3

Which bases are pyrimidines

Back 3

Cytosine and thymine

Front 4

How is a nucleotide formed

Back 4

1) a condensation reaction between carbon 1 of the sugar and nitrogen 9 of a purine base, or nitrogen 1 of a pyrimidine base results in the formation of a nucleoside, with the removal of water and the formation of an N-glycosidic bond.

2) another condensation reaction between the nucleoside and phosphoric acid results in a nucleotide. The bond formed between carbon 5 of the sugar and the phosphate group is a phosphodiester bond and results from the elimination of another water molecule

Front 5

What kind of bonds are the N-glycosidic bond and the phosphoester bond

Back 5

Both are strong covalent bonds

Front 6

What is a covalent bond

Back 6

A shared pair of electrons between two non metal atoms

Front 7

When guanine and cytosine pair up how many hydrogen bonds form

Back 7

3

Front 8

When guanine and cytosine pair up how many hydrogen bonds form

Back 8

3

Front 9

When thymine and adenine pair up how many hydrogen bonds form

Back 9

2

Front 10

When guanine and cytosine pair up how many hydrogen bonds form

Back 10

3

Front 11

When thymine and adenine pair up how many hydrogen bonds form

Back 11

2

Front 12

Name the method by which DNA replicates

Back 12

The semi conservative method

Front 13

Role of helicase

Back 13

Unwinds the double helix by breaking the hydrogen bonds between bases

Front 14

Role of helicase

Back 14

Unwinds the double helix by breaking the hydrogen bonds between bases

Front 15

Role of primase

Back 15

To lay down primer (complementary sequence of RNA bases)

Front 16

Role of helicase

Back 16

Unwinds the double helix by breaking the hydrogen bonds between bases

Front 17

Role of primase

Back 17

To lay down primer (complementary sequence of RNA bases)

Front 18

Role of DNA polymerase

Back 18

To add DNA nucleotides

Front 19

Role of ligase

Back 19

To join DNA fragments together by forming phosphodiester bonds

Front 20

Describe how the two strands of DNA are held together

Back 20

Complementary base pairs form hydrogen bonds

G-C - 3 hydrogen bonds

A-T - 2 hydrogen bonds

Front 21

Outline how the two strands of DNA are arranged

Back 21

Anti parallel

Forms Double helix

Bases toward centre

Sugar phosphate backbone

Front 22

Why does guanine only pair with cytosine and not thymine

Back 22

Cytosine has three groups which can form hydrogen bonds with guanine's three hydrogen bonding groups. Thymine has only one such group

Front 23

Role of RNA in DNA replication

Back 23

To act as a primer to provide a starting point for DNA polymerase

Front 24

For a cell to grow and divide what two processes must it's DNA be subject to

Back 24

Replication and mitosis

Front 25

For a cell to grow and divide what two processes must it's DNA be subject to

Back 25

Replication and mitosis

Front 26

Define replication

Back 26

The doubling of the chromosome complement to create two copies of each piece of DNA

Front 27

For a cell to grow and divide what two processes must it's DNA be subject to

Back 27

Replication and mitosis

Front 28

Define replication

Back 28

The doubling of the chromosome complement to create two copies of each piece of DNA

Front 29

Define mitosis

Back 29

Nuclear division that results in each daughter cell receiving a full chromosome complement

Front 30

Name the phases of the cell cycle

Back 30

Gap 1, synthesis of DNA, gap 2 and mitosis

Front 31

The phases are regulated, with movement from one phase to the next depending on the activity of cyclin dependent kinases what are cyclin dependent kinases?

Back 31

Enzymes that activate other proteins by adding phosphate groups

Front 32

The phases are regulated, with movement from one phase to the next depending on the activity of cyclin dependent kinases what are cyclin dependent kinases?

Back 32

Enzymes that activate other proteins by adding phosphate groups

Front 33

How do cyclin dependent kinases become active

Back 33

By binding to cyclins

Front 34

The phases are regulated, with movement from one phase to the next depending on the activity of cyclin dependent kinases what are cyclin dependent kinases?

Back 34

Enzymes that activate other proteins by adding phosphate groups

Front 35

How do cyclin dependent kinases become active

Back 35

By binding to cyclins

Front 36

Name the two proteins that control the cell cycle

Back 36

Cyclin dependent kinases and cyclins

Front 37

The phases are regulated, with movement from one phase to the next depending on the activity of cyclin dependent kinases what are cyclin dependent kinases?

Back 37

Enzymes that activate other proteins by adding phosphate groups

Front 38

How do cyclin dependent kinases become active

Back 38

By binding to cyclins

Front 39

Name the two proteins that control the cell cycle

Back 39

Cyclin dependent kinases and cyclins

Front 40

What happens in gap 1

Back 40

Cell growth and preparation of chromosomes for replication

Front 41

The phases are regulated, with movement from one phase to the next depending on the activity of cyclin dependent kinases what are cyclin dependent kinases?

Back 41

Enzymes that activate other proteins by adding phosphate groups

Front 42

How do cyclin dependent kinases become active

Back 42

By binding to cyclins

Front 43

Name the two proteins that control the cell cycle

Back 43

Cyclin dependent kinases and cyclins

Front 44

What happens in gap 1

Back 44

Cell growth and preparation of chromosomes for replication

Front 45

What happens in gap 0

Back 45

If free from damage cells enter the g0 phase where they carry out their functions while staying the same size and NOT preparing DNA for replication

Front 46

The phases are regulated, with movement from one phase to the next depending on the activity of cyclin dependent kinases what are cyclin dependent kinases?

Back 46

Enzymes that activate other proteins by adding phosphate groups

Front 47

How do cyclin dependent kinases become active

Back 47

By binding to cyclins

Front 48

Name the two proteins that control the cell cycle

Back 48

Cyclin dependent kinases and cyclins

Front 49

What happens in gap 1

Back 49

Cell growth and preparation of chromosomes for replication

Front 50

What happens in gap 0

Back 50

If free from damage cells enter the g0 phase where they carry out their functions while staying the same size and NOT preparing DNA for replication

Front 51

What happens during the S phase

Back 51

The level of S phase promoting factor increases. SPF which includes cyclin E, cyclin A and cdk 2 enters the nucleus and brings about the replication of DNA

Front 52

The phases are regulated, with movement from one phase to the next depending on the activity of cyclin dependent kinases what are cyclin dependent kinases?

Back 52

Enzymes that activate other proteins by adding phosphate groups

Front 53

How do cyclin dependent kinases become active

Back 53

By binding to cyclins

Front 54

Name the two proteins that control the cell cycle

Back 54

Cyclin dependent kinases and cyclins

Front 55

What happens in gap 1

Back 55

Cell growth and preparation of chromosomes for replication

Front 56

What happens in gap 0

Back 56

If free from damage cells enter the g0 phase where they carry out their functions while staying the same size and NOT preparing DNA for replication

Front 57

What happens during the S phase

Back 57

The level of S phase promoting factor increases. SPF which includes cyclin E, cyclin A and cdk 2 enters the nucleus and brings about the replication of DNA

Front 58

What happens during the mitosis phase

Back 58

Nuclear division and cytokinesis (division of cytoplasm) to give two new cells

Front 59

The phases are regulated, with movement from one phase to the next depending on the activity of cyclin dependent kinases what are cyclin dependent kinases?

Back 59

Enzymes that activate other proteins by adding phosphate groups

Front 60

How do cyclin dependent kinases become active

Back 60

By binding to cyclins

Front 61

Name the two proteins that control the cell cycle

Back 61

Cyclin dependent kinases and cyclins

Front 62

What happens in gap 1

Back 62

Cell growth and preparation of chromosomes for replication

Front 63

What happens in gap 0

Back 63

If free from damage cells enter the g0 phase where they carry out their functions while staying the same size and NOT preparing DNA for replication

Front 64

What happens during the S phase

Back 64

The level of S phase promoting factor increases. SPF which includes cyclin E, cyclin A and cdk 2 enters the nucleus and brings about the replication of DNA

Front 65

What happens during the mitosis phase

Back 65

Nuclear division and cytokinesis (division of cytoplasm) to give two new cells

Front 66

What is interphase

Back 66

The non mitotic phases of the cell cycle in which the cell grows and DNA replication occurs in preparation for the next cell division

Front 67

Describe prophase of mitosis

Back 67

Chromatids shorten and condense

The centrioles move apart to opposite poles of the nucleus

Two kinetochores appear on the centromeres of each dyad, one associated with each chromatid

The mitotic spindle fibres growing from each centriole attach to the kinetochores

The nuclear membrane disintegrates

Front 68

Describe metaphase of mitosis

Back 68

The dyads which are still attached to the poles by spindle fibres line up across the centre of the cell.

Front 69

Describe metaphase of mitosis

Back 69

The dyads which are still attached to the poles by spindle fibres line up across the centre of the cell.

Front 70

Describe anaphase of mitosis

Back 70

M phase promoting factor activates anaphase promoting factor (APC/C) by phosphorylation to begin anaphase

APC/C destroys cyclin B, a component of m phase promoting factor and securin, a protein that inhibits the enzyme separase

Released from inhibition, separase catalyses the breakdown of the cohesins that hold the sister chromatids together in a dyad

The pairs of kinetochores now separate and migrate to opposite poles of the cell, each dragging with them one of the chromatids from each dyad

APC/C also switches on the synthesis of cyclin d1, thus initiating the next cell cycle

Front 71

Describe telophase of mitosis

Back 71

The newly separated chromatids (now called chromosomes) are clustered at each end of the cell.

A nuclear membrane forms around each cluster

Front 72

Cytokinesis

Back 72

During telophase, cytokinesis, the separation of the cytoplasm occurs. In animal cells a belt of the protein actin forms around the middle of the cell, between the reformed nuclei. This belt of actin 'tightens' until it 'pinches' the cell into two daughter cells

Front 73

Cytokinesis

Back 73

During telophase, cytokinesis, the separation of the cytoplasm occurs. In animal cells a belt of the protein actin forms around the middle of the cell, between the reformed nuclei. This belt of actin 'tightens' until it 'pinches' the cell into two daughter cells

Front 74

What happens in plant cells

Back 74

In plant cells, a membrane bound cell plate forms on the site of the metaphase plate and new cell wall material is synthesised along that plate

Front 75

Discuss the checkpoints that occur during the cell cycle

Back 75

The are two checkpoints for DNA damage. One during gap 1 and then another during gap 2. There is also a spindle checkpoint that checks the formation and attachment of the spindles during the mitosis phase of the cell cycle

Front 76

Role of g1 checkpoint

Back 76

To prevent the replication of damaged DNA

Front 77

Role of g1 checkpoint

Back 77

To prevent the replication of damaged DNA

Front 78

Role of g2 checkpoint

Back 78

To prevent mitosis from occurring until DNA has been replicated successfully

Front 79

Role of m phase checkpoint

Back 79

To assess the formation of the spindles, check the attachments of fibres to the kinetochores and the direction in which the fibres pull the chromosomes

Front 80

What happens in meiosis 1

Back 80

The diploid gamete mother cell becomes two haploid daughter cells

Front 81

What happens in meiosis 1

Back 81

The diploid gamete mother cell becomes two haploid daughter cells

Front 82

What happens before meiosis 1 begins

Back 82

DNA replication (mitosis) occurs producing a dyad composed of paired daughter chromosomes

Front 83

What happens in meiosis 1

Back 83

The diploid gamete mother cell becomes two haploid daughter cells

Front 84

What happens before meiosis 1 begins

Back 84

DNA replication (mitosis) occurs producing a dyad composed of paired daughter chromosomes

Front 85

Describe prophase 1

Back 85

Homologous chromosomes line up to form bivalents (each containing four chromatids with two centromeres)

Spindle fibres emerge from the centrioles and kinetochores form on each chromosome dyad

The nuclear membrane disintegrates

Front 86

Describe metaphase 1

Back 86

The spindle attached bivalents line up across the metaphase plate

Front 87

Describe metaphase 1

Back 87

The spindle attached bivalents line up across the metaphase plate

Front 88

Describe anaphase 1

Back 88

The chromosome dyads are pulled apart by the spindle fibres to opposite poles of the cell

Front 89

Describe telophase 1

Back 89

The nuclear membrane reforms and cytokinesis commences. As each cell contains only one maternal or paternal version of each chromosome, these cells are haploid

Front 90

Give examples of events that occur in meiosis that contribute to greater genetic variation

Back 90

Independent assortment and crossing over