Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

biology > cell cycle and division > Flashcards

cell cycle and division Flashcards

1
Q

what are the stages of the cell cycle

A

Interphase
Mitosis
Cytokinesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happenes in Interphase

A

G1 phase - cell increases in size

S phase - DNA replicates by semi Conservative replication and starts to produce new organelles

G2 phase - cell prepares for division, Synthesis and stores of ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is nuclear division

A

period when nucleus divides into 2 (mitosis) or 4 (meiosis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is cytokinises (cell division )

A

division of cytoplasm which follows nuclear division and process by which cytoplasm divides to form 2 or 4 new cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what type of cells cannot undergo cell division

A

specialised cells, they must be made from stem cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

in what form is genetic information carried

A

in form of genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is a gene

A

section of DNA that codes for 1 specific polypeptide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are intergenic regions

A

regions in DNA sequence between the genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is a chromosome

A

it’s an independent DNA molecule which has been supercoiled into a condensed form , which carries a specific set of genes

( chromosomes contains many different genes )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does DNA supercoil using?

A

histone proteins

IN EUKARYOTIC CELLS ONLY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are 2 condenses DNA molecule called when theyre still joined

A

identical sister chromatids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is chromatin

A

DNA before supercoiling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are somatic cells

A

body cells and they have their chromosomes in homologous pairs

they are also diploid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are homologous chromosomes

A

have same genes in same gene loci but may have different alleles , one chromosome is maternal other is paternal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what does mitosis produce

A

2 diploid genetically identical daughter cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what happens in prophase

A

1) The nuclear membrane starts to break down.

2) The centrioles start to move to the poles of the cell and make spindle fibres.

3) The chromosomes supercoil and condense / shorten / thicken and become visible.

4) Each chromosome appears as 2 identical sister chromatids joined at the centromere

17
Q

what happens in metaphase

A

1)The centrioles complete the production of spindle fibres (contractile protein fibres)

2)The chromosomes are attached to the spindle fibres by their centromere

3) the chromosomes align down the equator of the cell

18
Q

what happens in anaphase

A

1) The spindle fibres contract/shorten.

2)The centromere splits

3)The identical sister chromatids are pulled to opposite poles

4) making a “V” shape

19
Q

what happens in telophase

A

1)A nuclear membrane starts to reform around each set of chromosomes

2)The chromatids / chromosomes unwind / uncoil / become longer / thinner and become invisible.

20
Q

Describe the appearance and behaviour of chromosomes during mitosis: [5 marks]

A
  1. During prophase, chromosomes supercoil and condense to become visible;
  2. Chromosomes appear as 2 identical sister chromatids joined by a centromere;
  3. During metaphase chromosomes line up on the equator of the cell;
  4. Chromosomes attach to the spindle fibres;
  5. By their centromeres;
  6. During anaphase, the centromere splits;
  7. Sister chromatids are pulled to opposite poles of the cell making a V shape;
  8. During telophase, chromatids uncoil and become thinner;
21
Q

what do tumour suppressor genes code for

A

Tumour suppressor genes code for proteins that slow down the cell cycle.

22
Q

what do proto-onco genes code for

A

Proto-onco genes code for proteins that speed up the cell cycle

23
Q

what is a tumour

A

mass of abnormal cells

24
Q

give one method for treating cancer

A

give drugs that inhibit cell division
these drugs may stop dna replication, spindle formation , cytokinises

25
give an example of asexual reproduction
binary fission in bacteria
26
describe binary fission
replication of the circular DNA (not associated with histones) and of plasmids The cell elongates from the middle, separating the two DNA molecules. A new cell wall (murein), is formed down the middle of the elongated cell which eventually meets, dividing the cell in two. division of the cytoplasm to produce two daughter cells, each with a single copy of the circular DNA and a variable number of copies of plasmids.
27
describe virus replication
1) Attachment proteins on the virus attach to the receptors on the cell. 2) The virus nucleic acid enters the cells cytoplasm. 3) *Reverse transcriptase makes DNA from viral RNA.* 4) The viruses DNA is inserted into the host cells own nuclear DNA / genome. 5) The viral DNA is transcribed (viral mRNA) and translated into viral proteins (capsids/enzymes/attachment proteins). 6) The cell replicates the viral DNA. 7) The genetic material and proteins coats are assembled into virions. 8) Eventually these virions burst out of the cell, often destroying the host cell.
28
where do viruses replicate and why
inside host cells, they use the host cells enzymes to replicate and transcribe viral DNA into viral mRNA translating into viral proteins bc they dont have own ribosomes nd dna
29
where does cell division in plants take place
root tips and shoot tips
30
before you view a plant sample you must add which 2 solutions
50 degrees HCL - to break down cellulose cell wall ensuring stain can enter ethano-orcein stain - to stain chromosomes and add contrast so they can be viewed under microscope
31
formula for mitotic index
number of cells in PMAT / total num of visible cells
32
why should you avoid moving the coverslip
it may damage / roll the chromosomes
33
what organisms do meiosis
organisms that reproduce sexually
34
what does meiosis produce
4 genetically different haploid daughter cells (gametes)
35
why is meiosis important
halves the chromosome number (ensuring each egg or sperm only has one copy of each chromosome n) before fertilisation to restore the full chromosome number at fertilisation 2n.
36
what are the stages of meiosis
P1 & M1: Chromosomes supercoil, condense (around histones) and become visible. Homologous pairs of chromosomes pair up (form a bivalent) and align along the equator. Spindle fibres attach to the centromere. Crossing over and independent segregation occurs here. A1 : Spindle fibres contract and separate homologous chromosome pairs, pulling one of each pair to opposite poles of the cell. T1 : Nuclear membrane reforms around the separated homologous chromosomes. Each daughter cell is now HAPLOID (n). P2 : Each daughter cell only contains one chromosome from each homologous pair (haploid). M2 : Each chromosome aligns along the equator. A2 : Non-Sister chromatids are split by their centromere and pulled to opposite poles of the cell. T2 : Nuclear membrane reforms. Four genetically different different haploid daughter cells are produced.
37
what is crossing over
1. The homologous chromosomes associate / Bivalent is formed. 2. Chiasma(ta) form (Chromosomes entangle / twist). 3. Equal lengths of (non-sister) chromatids / alleles are exchanged. 4. Producing new combinations of alleles.
38
when does crossing over happen
during metaphase 1
39
what is independent segregation
During Metaphase 1, maternal and paternal chromosomes are reshuffled in any combination on the equator of the cell

biology (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions