Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology A Level Content > 2.1.6 Cell Division, Cell Diversity and Cellular Organisation > Flashcards

2.1.6 Cell Division, Cell Diversity and Cellular Organisation Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What are the three main phases of the cell cycle?

A
  • Interphase
  • Nuclear division
  • Cytoplasmic division (cytokinesis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens in the G1 phase?

A
  • Growth
  • Proteins and organelles are made
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happens in the S phase?

A
  • Replication of DNA (synthesis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What happens in the G2 phase?

A
  • Organelles made
  • Energy stores increased
  • DNA is checked for errors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does a checkpoint do?

A

Verify that the previous part of the cell cycle has been completed
e.g. G1, G2, spindle assembley

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

What is the G1 checkpoint?

A
  • Between G1 and S phases
  • Checks for cell size, nutrients, growth factors and DNA damage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the G2 checkpoint?

A
  • Between G2 and nuclear division phases
  • Checks for cell size, DNA replication and DNA damage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the spindle assembly (metaphase) checkpoint?

A
  • At metaphase
  • Checks that chromosomes are aligned and attached to spindles at the centromeres
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is G0?

A
  • When a cell leaves the cell cycle
  • Happens when checkpoints aren’t satisfied
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why does a cell enter G0?

A

Differentiation:
- Cell becomes specialised
- Performs this function indefinitely

Damaged DNA:
- Can no longer replicate (senescent)

Age:
- The older you are, the more senescent cells you have
- Linked with cancer and arthritis

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

What is cancer and how is it caused?

A
  • Caused by mutation of genes that regulate the cell cycle
  • Uncontrolled growth of cells
  • Forms a tumour
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How can cancer be treated?

A
  • Prevent DNA replicating or inhibit metaphase (interfere with spindle fibres)
  • Can be done using cisplastin or vinca alkaloids
  • Treating cancer also affects normal cells and can cause hair loss
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the stages of mitosis?

A
  1. Interphase
  2. Prophase
  3. Metaphase
  4. Anaphase
  5. Telophase
  6. Cytokinesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens in interphase?

A
  • Chromosomes are invisible prior to mitosis
  • Long and thin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens in prophase?

A
  • Chromosomes condense and become visible
  • Nuclear envelope and nucleolus disappear
  • Centrioles move to the opposite ends of the cell
  • Spindle fibres attach to centromeres and start to move chromosomes to the equator
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens in metaphase?

A
  • Chromosomes arrange themselves along the equator of the cell
  • Equator is known as the metaphase plate
17
Q

What happens in anaphase?

A
  • Each of the 2 threads of the chromosome (chromatid) migrates to an opposite pole by shorting spindle fibres
18
Q

What happens in telophase?

A
  • Nuclear envelope reforms
  • Nucleolus reforms
  • Chromosomes uncoil and become long and thin again
19
Q

What happens in cytokinesis?

A
  • Cell divides into 2 daughter cells that are identical to the parent cell
  • Division of the cytoplasm
20
Q

What is the difference between a chromatid and chromosome?

A

1 chromosome is made of 2 chromatids

21
Q

What is the process of cytokinesis in animal cells?

A
  • Cleavage furrow forms in the middle of the cell
  • Cell surface membrane is pulled inwards by the cytoskeleton and fuses
22
Q

What is the process of cytokinesis in plant cells?

A
  • Plant cells have a cell wall which prevent a cleavage furrow
  • Vesicles from the golgi apparatus line up along the metaphase plate
  • Vesicles fuse with each other and the cell surface membrane
  • New cell wall forms
23
Q

What is the importance of mitosis?

A
  • Growth
  • Differentiation
  • Repair
  • Asexual reproduction in plants, animals and fungi
24
Q

Why are plant root tips a good source of cells for mitosis?

A
  • Continually growing at regions called meristems
  • Meristems are constantly dividing
25
Q

How do you calculate mitotic index?

A

Mitotic index = number of actively dividing cells in field of view/number of cells in field of view

26
Q

What are homologous chromosomes?

A
  • The same genes in the same positions (could be different alleles)
  • One from each parent
  • Same length and size
27
Q

What is an allele?

A

Different versions/forms of a gene

28
Q

What is a locus?

A

Where on the chromosomes the alleles are

29
Q

What is a gamete?

A

A haploid cell involved in sexual reproduction (e.g. egg and sperm or pollen and egg)

30
Q

What does haploid mean?

A

Half of the number of chromosomes

31
Q

What does diploid mean?

A

Full number of chromosomes

32
Q

How is genetic variation created?

A
  • Crossing over
  • Independent segregation of chromosomes (random assortment)
  • Random fertilisation
33
Q

What is crossing over?

A
  • When chromatids twist around each other and swap
  • Contain the same genes but different alleles
  • Only within homologous pairs
34
Q

What is the independent segregation of chromosomes?

A
  • Chromosomes align on the metaphase plate randomly during metaphase (meiosis I)
  • One from each pair passes into a daughter cell
35
Q

What is random fertilisation?

A
  • Any sperm can fertilise any egg
  • Each individual is unlike any to have existed before or any that will exist again
36
Q

What are the main stages of meiosis?

A
  1. Interphase
  2. Meiosis I
  3. Meiosis II
37
Q

What happens in interphase?

A
  • DNA duplicates during S phase
38
Q

What happens in meiosis I?

A
  • The first division
  • Each chromosome is made up of two sister chromatids
  • Genetic recombination takes place at random (chromosomes cross over and swap blocks of genes)
  • Prophase I, metaphase I, anaphase I and telophase I
  • Homologous chromosomes segregate into 2 nuclei
  • Nuclear envelope forms
39
Q

What happens in meiosis II?

A
  • The second division
  • Identical to mitosis
  • Prophase II, metaphase II, anaphase II and telophase II
  • Chromatids from individual chromosomes are pulled to opposite poles
  • Independent assortment
  • 4 haploid gametes form
  • Known as reduction division

Biology A Level Content (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions