D2.1 Cell and Nuclear Division

Question 1

Define cytokinesis (2)

Answer 1

physical process of cell division

divides cytoplasm of parental cell into 2 daughter cells

Question 2

Define the mother cell

Answer 2

parent cell/original cell

Question 3

Define the daughter cell

Answer 3

mother cell divides into 2 daughter cells

Question 4

Prokaryotic division

Answer 4

divide by binary fission

Question 5

Eukaryotic division

Answer 5

divide by mitosis or meiosis

Question 6

How cytokinesis works for animal cells (2)

Answer 6

network of actin + myosin proteins form a contractile ring that pinches cell membrane together

forms a cleavage furrow - deepens and forms 2 separate daughter cells

Question 7

How cytokinesis works in plant cells (2)

Answer 7

formation of cell plate - created by fusion of vesicles containing cell wall material (cellulose)

cell plat grows outward until it reaches the existing cell wall that it fuses with

Question 8

Describe equal cell division (2)

Answer 8

daughter cells receive at least 1 mitochondria + other organelles come from existing parent cells

produces 2 cells of the same size

Question 9

2 examples of unequal cell division

Answer 9

Oogenesis

Budding in yeast

Question 10

Describe oogenesis (3)

Answer 10

primary oocyte (2n) performs cell division + releases first polar body (n)

Secondary oocyte loses a second polar body and become ovum

ovum fertilised by sperm cell to form zygote

Question 11

Describe Budding in yeast (3)

Answer 11

type of asexual reproduction

bud starts small then grows until it becomes a fully developed cell

daughter cell is is typically smaller than parent cell and receive less than half of cytoplasm + organelles

Question 12

Define mitosis (2)

Answer 12

process of nuclear division before a cell physically divides into 2

cell’s DNA is copied into 2 daughter cells before mitosis

Question 13

Define interphase (2)

Answer 13

stage where DNA is replicated

occurs before mitosis

Question 14

Stages of mitosis (4)

Answer 14

prophase

metaphase

anaphase

telophase

Question 15

Importance of mitosis (2)

Answer 15

how organisms grow

important for asexual reproduction

Question 16

Structure of chromosomes (2)

Answer 16

chromosomes are only visible during cell division

2 chromatids joined at centromere to form x-shape

Question 17

Describe early prophase (4)

Answer 17

chromosomes become more distinct

coil up

shorten

thincken

Question 18

Describe late prophase (3)

Answer 18

centrioles move towards opposite poles of the cell

nucleolus shrinks + disappears

nuclear envelop disintegrates

Question 19

Describe metaphase (2)

Answer 19

centrioles at poles grow/produce spindle fibers

spindle fibres attach to centrometre of chromosomes

Question 20

Describe anaphase (3)

Answer 20

spindle fibres contract

chromatids are pulled to opposite poles of cells by their centromere

each pole receives one chromatid from each chromosome

Question 21

Describe telophase

Question 22

Define cell proliferation (2)

Answer 22

process of cellular division/replication

increases cell number and/or organism size + complexity

Question 23

Stages of interphase (4)

Answer 23

first growth phase

G0 phase

synthesis phase

second growth phase

Question 24

Functions at site of interphase (4)

Answer 24

DNA replication + checked for errors

protein synthesis

mitochondria + chloroplasts grow and divide

metabolic functions

Question 25

First growth phase of interphase (3)

Answer 25

proteins are synthesized organelles replicate cell increases in size

Question 26

Synthesis phase of interphase

Answer 26

DNA is replicated in the nucleus

Question 27

Second growth phase of interphase (3)

Answer 27

cell continues to increase in size energy stores increase duplicated DNA checked for errors

Question 28

G0 phase of interphase

Answer 28

cell moves out of the cell cycle can be permanent or temporary

Question 29

Reasons for G0 phase of interphase (2)

Answer 29

cell becomes specialised to carry out particular function DNA is damaged - cell division may no longer be viable

Question 30

cyclin D level of G1 phase

Answer 30

cyclin D levels gradually increase

Question 31

cyclin E level of S phase

Answer 31

cyclin E is used for DNA replication + promotes centromere duplication

Question 32

cyclin A level of G2 phase

Answer 32

helps induce DNA replication

Question 33

cyclin B level of mitosis

Answer 33

essential for formation of mitotic spindles + alignment of chromatids

Question 34

Define malignant tumour (2)

Answer 34

cancer cells in tumour spread to other parts of body sometimes recur after it is removed

Question 35

Define benign tumour (2)

Answer 35

localised and does not spread to other parts of body most respond well to treatment

Question 36

Stages of meiosis (2)

Answer 36

Meiosis 1 Meiosis 2

Question 37

Meiosis 1 Prohpase 1

Answer 37

chromosomes condense nuclear envelope disintegrates spindle fibres form on poles crossing over - exchange of equivalent DNA between non-sister chromatids DNA molecule of one chromatids is cut + second cut is made at same point of other chromatid from other parent (non-sister) DNA sections are swapped between parent chromosomes

Question 38

Meiosis II