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Biology, Module 2 OCR > Cell Cycle, Division and organisation > Flashcards

Cell Cycle, Division and organisation Flashcards

1
Q

What happens in G0

A

Cells do not replicate, just respire and do normal metabolic reactions

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2
Q

Checkpoints (5)

A

At the end of each stage, checkpoints confirm if cell is able to progress

G1 checkpoint: cell size, nutrients, growth and DNA damage
G2: cell size, DNA replication, DNA damage
Spindle assembly checkpoint: At the metaphase stage in mitosis, this checks all the chromosomes are attached to spindle fibres

Failure at checkpoints lead to apoptosis.

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3
Q

Apoptosis

A

Programmed cell death

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4
Q

Homologous chromosomes (5)

A
  • 23 chromosomes from each parent
Same;
length 
Bonding pattern 
Type of gene 
Centromere position
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5
Q

Four phases of mitosis

A

Prophase

Metaphase

Anaphase

Telophase

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6
Q

Prophase (4)

A

Chromatin condenses to form chromosomes

Chromatids held by centromeres

Nuclear envelope disappears

Centrosomes form spindle fibres

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7
Q

Metaphase (4)

A

Chromosomes attach to spindle fibres

Motor proteins help with movement

(Protein E in centromere help pull chromosomes into 2)

Chromosomes line down metaphase plate

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8
Q

Anaphase (2)

A

Motor proteins pull on spindle fibres- s.f shorten

Chromosomes are split to either side of cell

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9
Q

Telophase (2)

A

Nuclear membrane constructed around chromosomes

Nuclear envelope constructed

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10
Q

Cytokinesis (2)

A

New cell membrane is formed

Cell splits to form two identical daughter cells

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11
Q

Interphase (name 6 processes that occurs in this phase)

A

All the processes before mitosis

  • genetic material copied
  • cell growth
  • organelle replication
  • ATP production
  • proteins synthesis
  • checking of DNA
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12
Q

Purpose of mitosis (4)

A

Cell replacement

Tissue repair

Organism/ tissue growth

Asexual reproduction

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13
Q

Location of mitosis

A

Every cell but gametes

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14
Q

Product of mitosis

A

2 genetically identical

diploid daughter cells

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15
Q

Purpose of meiosis

A

Creates gametes in animals

Creation of spores in fungi and plants

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16
Q

Location of meiosis

A

Reproductive organs in animals

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17
Q

Product of meiosis

A

4 haploid daughter cells

genetically unique

Mix of DNA from both parents

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18
Q

Events that occur in G1

A

Cell growth

Protein synthesis

Organelles duplicate

Transcription

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19
Q

Features and function of neutrophils (4)

A

Ingests and destroy invading microorganisms

Lobed nucleus; squeeze through small gaps and vessels

Granular cytoplasm; contains lysosomes which release enzymes to attack pathogens

10-14 micro meters

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20
Q

Erythrocytes functions and structure (5)

A

Carries oxygen in the blood.

Haemoglobin; binds to oxygen

No nucleus; more space for haemoglobin

Bio concave; greater SA:V ratio

Flexible; squeeze through tiny capillaries

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21
Q

Squamous epithelium function and features (2)

A

Flat, single layered, smooth cells; covers a large area

Basement membrane; collagen and glycoproteins that binds to connective tissue. Used for cell signalling and cell adhesion.

Thin: short distance for diffusion

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22
Q

Ciliated epithelium (4)

A

Removes particles that shouldn’t be in lungs

Column shaped

Cilia hairs bear in synchronises pattern that help remove dust and other particles

Goblet cells produce mucus to trap dust and etc

23
Q

Sperm cells (5)

A

Male gamete in sexual reproduction; delivers genetic information to the ovum

Undulipodium; tail that propels the cell.

Acrosome; lysosomes that penetrate ovum coat leading to fertilisation

Small and thin; Allows easier movement

Many mitochondria: Allows release of energy for movement.

24
Q

Xylem (4)

A

Transportation of water and minerals UP plants

Vessel elements; elongated dead cells

Ligin; waterproof walls for dead cells, provides structural support

Wide lumen; space for material and gives tube structure

25
Q

Phloem (3)

A

Transportation of organic nutrients up and down plants

Transporta sucrose esp from leaves and stem to where it is needed

Sieve tubes and plates

26
Q

Palisade cells (5)

A

In mesophyll(leave cells); contains chloroplast to absorb light for photosynthesis

Rectangular boxes shape; pack tightly in continuous column to Maximise absorption

Large vacuole; turgor pressure, restricting chloroplast to edge of cell

Thin cell walls; quick diffusion of gas for photosynthesis

Cytoplasmic streaming: Movement of fluid inside the cell which moves chloroplast around

27
Q

Guard cells (5)

A

Control the stomatal opening

Large vacuole; takes up water and expands to open the stomata.

Unevenly thickened cell wall; allows cell to change shape as it becomes turgid

Mitochondria; ATP for active transport

Active pumps in plasma membrane: Allows mineral ions to be transported in and out of cell to control water potential.

28
Q

Root hair cells (3)

A

Long extensions; large surface area for more absorption

Active pumps in plasma membrane: actively absorb minerals ions.

Thin cell wall: Decreases barrier for transport of water and mineral ions.

29
Q

What is a stem cell (3)

A

Unspecialised cell

Capable of mitosis

Able to become other cell types

30
Q

Totipotent potency and examples (3)

A

Stem cells that can specialise into ANY type of cell

Can produce whole organisms

Eg fertilised eggs, zygotes

31
Q

Pluripotent potency (3)

A

Stem cells that can form all tissue types

Can’t form whole organisms

In early embryos

32
Q

Multipotent potency (3)

A

Stem cells that form a range of cells

Within a certain type of tissue

Eg haematopoetic cells in bone marrow

33
Q

Where do all blood cells derive from

A

Bone marrow

34
Q

Sources of animal stem cells (2)

A

Embryonic; totipotent until it becomes a blastocyst
Then is pluripotent until birth

Adult; bone marrow, umbilical cord
Multipotent can be trigger to pluripotent

35
Q

Advantages of using umbilical cord instead of bone marrow (4)

A
  • less invasive surgery
  • more plentiful source
  • cannot be rejected from umbilicus owner
  • can be stored for later use
36
Q

Meritstem (5)

A

Stem cells in plants

Found in growing tissue; tips of root and shoots

Between phloem and xylem- vascular cambium

Differentiation occurs from there

Pluripotent for the lifetime

37
Q

Vascular cambium (2)

A

Where meristem tissue is located- between xylem and phloem

Cell differentiation happens from this region

38
Q

Organ

A

Collection of tissue adapted to perform certain function in an organism

Eg heart pumps blood

39
Q

Organ system

A

Collection of organs working together to carry out a major function

Eg digestive, cardiovascular, gaseous exchange

40
Q

Tissue

A

Collection of differentiated cells that have specialised function

41
Q

Describe the ultra structure of a neutrophil enables it to perform its function (6)

A
  • Lysosomes to secrete enzymes
  • Many ribosome, mitochondria, microfilaments and receptor sites
  • lots of Golgi
42
Q

How does plant cell division differ from animal? (3)

A
  • cell wall is between plant cells
  • cytokinesis starts from the middle in plants
  • only occurs in the meristem in plants
43
Q

Reduction division

A

When a cell divides to form a haploid cell from diploid

  • first division in Meiosis 1
44
Q

Propose 1 (5)

A
  • Chromosomes condense
  • Homologous chromosomes pair up to form bivalents
  • nuclear envelope disintegrates and spindle fibres form
  • Crossing over of chromosomes between non-sister chromatids occur at chiasmata
45
Q

Metaphase 1 (2)

A
  • Chromosomes are lined up at equator by spindle fibres

- Independent assortment of chromosomes sets orientation of maternal/paternal chromosomes to different poles of the cell

46
Q

Anaphase 1 (3)

A
  • Spindle fibres shorten and break chromosomes by chiasmata
  • Recombinant chromosomes formed when crossed over sections join when they are pulled apart
  • this forms new combinations of DNA (leads to genetic variation)
47
Q

Telophase 1(3)

A
  • Chromosomes settle at each pole of the cell and condense
  • nuclear envelop reforms
  • cell divides at cell equator( formation of cell membrane) via cytokinesis
48
Q

Prophase 2 (2)

A
  • Chromosomes condense

- nuclear envelope disintegrates whilst spindle fibres form

49
Q

Metaphase 2

A
  • Chromosomes are lined up by spindle fibres on equator plate
  • Independent assortment of chromatids occurs where genetically unique chromatids are orientated at different poles of the cell
50
Q

Anaphase 2

A
  • Spindle fibres pull apart chromosomes by centromere so each pole has chromatids
51
Q

Telophase 2 (3)

A
  • Chromosomes uncoil and settle at opposite poles
  • nuclear envelope develops
  • cytokinesis occurs at the cell equator
52
Q

How does crossing over cause genetic variation

A
  • non-sister chromatids entangle at the chiasmata

- exchange of alleles occur which produces new combinations of alleles

53
Q

How does independent assortment cause genetic variation (2)

A
  • Homologous chromosomes orientation in metaphase 1 (chromosomes) and metaphase 2 (chromatids) are independent
  • formation of new combinations of alleles occur due to assignment of chromosomes to individual cells
54
Q

Importance of creating genetic variation in meiosis (3)

A
  • Genetically diverse population is important for natural selection
  • Allows opportunity for individuals to obtain traits that may be beneficial in a changing environment
  • no variation would mean that the population would be vulnerable to selection pressures and there would be no opportunity for adaptations

Biology, Module 2 OCR (11 decks)

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