Brainscape's Knowledge GenomeTM

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


See full index

Biology OCR A A level > Cell Division > Flashcards

Cell Division Flashcards

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

What are the two main phases of eukaryotic cell cycle?

A

Interphase

Mitotic Phase

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

What 5 things are occurring during interphase?

A

1) DNA replicated and checked for errors in nucleus
2) Protein synthesis occurs in cytoplasm
3) Mitochondria grow and divide, increasing no. in cytoplasm
4) Chloroplasts grow and divide
5) Normal metabolic processes of cells occur

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

What are the 3 stages of interphase?

A

G1, S, G2

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

What happens in G1?

A

Organelles are replicating
Proteins being synthesised
Cell increases in size

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

What happens in S?

A

Synthesis phase- DNA is replicated in nucleus

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

What happens in G2?

A

Cell continues to increase in size
Energy stores are increased
Duplicated DNA is checked for errors

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

What are the 2 parts of the mitotic phase?

A

Mitosis- nucleus divides

Cytokinesis- the cytoplasm divides and two cells are produced

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

What is G0?

A

The phase of the cell cycle where a cell leaves the cycle either temporarily or permanently

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

What are main 3 reasons a cell leaves the cell cycle?

A

Differentiation
DNA or cell damage
Old age

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

What is the role of checkpoints in the cell cycle?

A

Control mechanisms of cell cycle. They monitor and verify whether the process has accurately occured

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

When does the G1 checkpoint occur? What does it check for?

A

End of G1 before S

Checks for: cell size, nutrients, growth factors, DNA damage

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

When does the G2 checkpoint occur? What does it check for?

A

End of G2 before mitosis

Checks for: cell size, DNA replication, DNA damage

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

When does spindle assembly checkpoint occur?

A

At the point in mitosis when all the chromosomes should be attached to spindles and been aligned

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

Why is mitosis important?

A

Growth of tissues
Replacement of damaged cells
Asexual Reproduction

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

Why do prokaryotic cells not divide by mitosis?

A

Don’t have a membrane bound nucleus or spindle fibres so divide by binary fission instead

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

Before mitosis occurs, DNA is replicated, how is this then arranged?

A

DNA replicated

2 identical sister chromatids joined by centromere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is chromatin and what is its role?

A

Chromatin is a complex of DNA and histones

Helps to package DNA in a compact way that can fit inside the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What 5 things occur during prophase in mitosis?

A

1) Chromosomes coil and condense
2) Nucleolus disappears
3) Nuclear membrane starts to break down
4) Protein microtubules form the spindle
5) Centrioles migrate to opposite poles of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What 2 things occur in metaphase in mitosis?

A

1) Chromosomes are moved by spindle fibres to the equator of the cell
2) Chromosomes line up on the metaphase plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What 3 things occur in anaphase in mitosis?

A

1) Centromeres divide
2) Spindle fibres shorten
3) Sister chromatids are separated and pulled to opposite poles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What 4 things occur in telophase in mitosis?

A

1) Chromosomes reach poles
2) Nuclear envelope forms around each set of chromosomes
3) Chromosomes uncoil
4) Nucleolus reforms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is cytokinesis?

A

The division of the cytoplasm to produce two new cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Explain process of cytokinesis in animals

A

The cell-surface membrane is pulled inwards
Cleavage furrow formed
Cytoskeleton (actin filaments) pull close enough until fuses around the middle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Explain process of cytokinesis in plants

A

Vesicles travel along and assemble in the same place as metaphase plate
Vesicles fuse to each other and the cell membrane
Divides cell membrane in two
Cellulose is laid down between the new cell membrane to maintain shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Give 3 adaptations of erythrocytes and explain how this helps them

A

Flattened Biconcave Shape- gives larger surface area to volume ratio
Don’t have nuclei- Space for other organelles and haemoglobin
Flexible- pass through narrow capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Give 2 adaptations as neutrophils(white blood cell) and explain the role of these

A

Multi-lobed nucleus so can squeeze through small gaps to get to site of infection
Granular cytoplasm- contains lysosomes with enzymes to attack pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Give 3 adaptations of sperm cells and explain the role of these

A

Flagella- for movement
Many mitochondria- provides energy for swimming
Acrosome- contains digestive enzymes to digest protective layer of the ovum, so egg can be fertilised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Give 5 adaptations of palisade cells and explain the role of these

A

Lots of chloroplasts- absorb large amounts of light
Rectangular box shape- packed tightly in a continuous layer
Thin walls-increase rate of diffusion of CO2
Large vacuole- maintain turgor pressure
Chloroplasts can move- absorb more light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Give an adaptation of a root hair cell and explain the role of this

A

Large long extensions which increases surface area of cell, maximising uptake of water and minerals from soil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Give 2 adaptations of guard cells/stoma and explain the role of these

A

Guard cells change shape and stoma close- to prevent further water loss from the plant
Cell wall of guard cell thicker on one side- doesn’t change shape symmetrically as volume changes

31
Q

Define ‘tissue’

A

Tissue is made up of differentiated cells that have a specialised function or functions.

32
Q

What are the 4 main categories of tissue in animals?

A

Nervous tissue
Epithelial tissue
Muscle tissue
Connective tissue

33
Q

What are the adaptations of each of the 4 main categories of tissue?

A

Nervous tissue- support transmission of electrical impulses
Epithelial tissue- cover body surfaces
Muscle tissue- adapted to contract
Connective tissue- adapted to hold tissues together

34
Q

Give an adaptation of squamous epithelium. Give an example of where it is present.

A

Thin- due to being one cell thick- allows for rapid diffusion
In lining of lungs

35
Q

Give two adaptations of ciliated epithelium. Give an example of where it is present.

A

Cilia present which sweep mucus away
Goblet cells also present, releasing mucus to trap pathogens
Present in trachea

36
Q

What is cartilage adapted to prevent?

A

Prevents ends of bones from rubbing together and causing damage.

37
Q

What is muscle tissue adapted to do?

A

Shorten and lengthen in order to move bones

38
Q

What are 2 main tissues in plants? Give their main adaptation

A

Epidermis Tissue- adapted to cover plant surfaces

Vascular tissue- adapted for transport of water and nutrients

39
Q

How is the epidermis of plant adapted for its function? (3 ways)

A

Single layer of closely packed cells covering the surfaces of plants
Covered in waterproof, waxy cuticle to reduce water loss
Stomata present in epidermis

40
Q

How is the xylem tissue adapted for function, structurally?

A

Walls are strengthened by lignin which provides structural support for plants

41
Q

Define ‘organ’

A

A collection of tissues that are adapted to perform a particular function in an organism

42
Q

Define ‘organ system’

A

Each organ system working together in a coordinated manner to carry out major function.

43
Q

What is the mitotic index a measure of?

A

A quantitative expression of the amount of cell division happening within a tissue

44
Q

What is the equation for the mitotic index?

A

MI= number of cells with condensed chromosomes/ total number of cells x 100

45
Q

Define diploid

A

Normal chromosome number, two chromosomes of each type one inherited from each parent

46
Q

How many daughter cells does meiosis form?

A

4

47
Q

Define haploid

A

Half of the chromosome number of parent cell

48
Q

What type of division is meiosis?

A

Reduction Division

49
Q

Define ‘homologous chromosomes’

A

Matching pair of chromosomes, one inherited from each parent.

50
Q

What is an allele?

A

Different version of same gene

51
Q

What occurs during Meiosis 1?

A

Reduction division, the homologous chromosomes are separated into two cells. Each intermediate cells contains only one full set of genes.

52
Q

What occurs during Meiosis 2?

A

Similar to mitosis, pairs of chromatids are separated forming two more daughter cells. 4 haploid cells produced in total.

53
Q

What 5 things occur during Prophase 1?

A 
Chromosomes condense
Nuclear envelope breaks down
Nucleolus disappears
Homologous chromosomes pair up (bivalents)
Crossing over occurs- causing variation
54
Q

What occurs during Metaphase 1?

A

Homologous pairs of chromosomes line up randomly along metaphase plate
The maternal or paternal chromosomes end up facing each pole- Independent Assortment

55
Q

What occurs during Anaphase 1?

A

Spindle fibres form an attach to centromere
Crossing over that occurred in prophase, break off and rejoin and fuse. The fuse is called chiasmata.
Sister chromatids no longer identical

56
Q

What 4 things occur during Telophase 1?

A

Chromosomes assemble at each pole
Chromosomes uncoil
Cell undergoes cytokinesis
Reduction in chromosomes from diploid to haploid

57
Q

What 3 things occur during Prophase 2?

A

Chromosomes condense and become visible again
Nuclear envelope breaks down
Spindle fibres form

58
Q

What happens during Metaphase 2?

A

Chromosomes assemble on metaphase plate

Due to crossing over there is more independent assortment, and so more genetic variation

59
Q

What occurs during Anaphase 2?

A

Chromatids are pulled to the poles of the cell

60
Q

What occurs during Telophase 2?

A 
Chromatids assemble at poles 
Chromosomes uncoil and chromatin forms again
Nuclear envelope forms
Nucleolus forms
Cytokinesis forms 4 daughter cells
61
Q

What are stem cells?

A

Undifferentiated cells

62
Q

What 3 things are stem cells necessary for?

A

Growth, Development, Tissue Repair

63
Q

What is ‘potency’?

A

A stem cell’s ability to differentiate into different cell types

64
Q

Define a ‘totipotent cell’. Give examples.

A

Stem cells that can differentiate into any cell type

Fertilised egg, zygote, cell in first few mitotic divisions

65
Q

Define a ‘pluripotent cell’. Give examples.

A

Stem cells that can form all tissue types but not whole organisms.
Early embryos

66
Q

Define a ‘multipotent cell’. Give examples.

A

Stems cells that can form a range of cells within a certain type of tissues
Haematopoietic cells in bone marrow

67
Q

Where are all blood cells derived from?

A

Bone marrow

68
Q

When does an embryo go from totipotent to pluripotenet?

A

At about 7 days when a mass of cells called blastocyst has formed

69
Q

What are the advantages of harvesting stem cells from umbilical cords?

A

Plentiful supply

Invasive surgery not required

70
Q

What are the sources of animal stem cells?

A

Embryonic stem cells

Tissue stem cells

71
Q

What are the sources of plant stem cells?

A

Meristematic tissue found in all growing areas of pants

72
Q

Give 7 areas of medicine where stems cells have the possibility to treat disease

A 
Heart disease
Type 1 diabetes
Parkinson's disease
Alzheimer's disease
Macular Degeneration
Birth defects
Spinal injuries
73
Q

Give 3 areas of science where stem cells are already used

A

Treatment of burns
Drug trials
Developmental biology

74
Q

Why are there ethical issues surrounding stem cells?

A

Embryos are destroyed in process
People see it as murder
Religious views

Biology OCR A A level (17 decks)

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