2.6 Cell divison and organisation Flashcards

1
Q

What stages are in the cell cycle?

A

Gap 1 phase
G1checkpoint
S phase
Gap 2 phase
G2 checkpoint
M phase

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2
Q

What does the M phase involve?

A

Mitosis and cytokinesis

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3
Q

What parts of the cell cycle happen in interphase?

A

All but M Phase
so G1 G1 checkpoint S G2 G2 checkpoint

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4
Q

What happens in G1 phase?

A

Cell growth and new organelles and proteins are made.

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5
Q

What happens at G1 checkpoint?

A

The cell checks for any damage to FNA and checks chemicals needed for replication are present.

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6
Q

What happens in the S phase?

A

Cells DNA replicates.

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7
Q

What happens in G2 phase?

A

Cell keeps growing and more proteins for cell division are made.

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8
Q

What happens in the G2 checkpoint?

A

The cell checks DNA has been replicated with no damage. If no damage allows cell to enter mitosis

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9
Q

What happens during interphase ?

A

Cell carries out normal functions and prepares to divide. DNA unravels and replicates. Organelles replicate and extra ATP produced.

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10
Q

What stages are in Mitosis?

A

Prophase , Metaphase , Anaphase, Telophase.

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11
Q

What happens in Prophase?

A

Chromosomes condense and centrioles move to poles of cell forming spindle fibres.
Nuclear envelope breaks down.

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12
Q

What happens during metaphase?

A

Chromosomes line up along middle of cell. (M for middle).
The chromosomes attach to the spindle fibres at there centromeres.
Then a metaphase checkpoint occurs where they check for all chromosomes being attached to spindle fibres before mitosis can continue

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13
Q

What happens during Anaphase?

A

Centromeres divide and separate sister chromatids. Spindle fibres contract pulling chromatids to centromeres at poles.

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14
Q

What happens during Telophase?

A

Chromatids reach poles and uncoil to become chromosomes again. New nuclear envelopes form around each group of chromosomes.

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15
Q

What happens during cytokinesis?

A

The cytoplasm divides by forming a cleavage furrow.

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16
Q

What does mitosis produce?

A

Two diploid genetically identical daughter cells.

17
Q

What does meiosis produce?

A

four haploid genetically different daughter cells.
Produces gametes

18
Q

What is diploid and haploid

A

diploid = has 2 chromosomes (a pair)
Haploid = only 1 chromosome (half)

19
Q

What are the stages in Meiosis?

A

Interphase
Meiosis 1 with prophase metaphase anaphase telophase + cytokinesis
Meiosis 2 with prophase 2 metaphase 2 anaphase 2 telophase 2 + cytokinesis

20
Q

How is genetic variation in gamete’s produced/ made?

A
  1. Crossing over of chromatids
  2. Independent assortment of chromosomes
21
Q

How does crossing over of chromatids create genetic variation?

A

The chromatids twist around each other in cell division and bits of chromatid swap over. They contain the same genes but now have different alleles.

22
Q

Where does crossing over occur?

A

In prophase 1 of meiosis 1.

23
Q

How does independent assortment cause genetic variation?

A

When the homologous pairs of chromosomes line up in metaphase 1 and separate its random which chromosome from each pair ends up in which daughter cell.

24
Q

When does independent assortment occur?

A

During Metaphase 1 of meiosis 1

25
Q

What is a stem cell?

A

An unspecialised cell. They have the ability to develop into different types of cell.

26
Q

What stems cells do humans have?

A

Embryonic stem cells.
Adult stem cells found in bone marrow .

27
Q

What is differentiation?

A

When cells divide to become new ones and become specialised.

28
Q

What do adult stem cells mainly do?

A

Replace worn out blood cells (erythrocytes rbc or neutrophils wbc)

29
Q

What stem cells do plants have and what do they specialise into?

A

Stem cells found in meristem and can divide to become xylem and phloem sieve tubes in the roots

30
Q

What are 3 examples of specialised cells in animals? Explain there structure

A
  1. erythrocytes - biconcave shape so large surface area, No nucleus so more room for haemoglobin.
  2. Neutrophils - Flexible shape so can engulf stuff, Lots of lysosomes to break down engulfed stuff.
  3. Epithelial cells- Have interlinking membranes, have cilia or microvilli to increase SA.
31
Q

what is a tissue?

A

A group of cells that are specialised to work together to carry out a particular function. It can have more then one type of cell

32
Q

What are examples of animal tissues?

A
  1. squamous epithelium
  2. Muscle tissue
  3. Cartilage
  4. Ciliated epithelium
33
Q

what are examples of plant tissues?

A
  1. Xylem tissue.
  2. Phloem tissue.
34
Q

What is an organ?

A

A group of different tissues that work together to perform and particular function.

35
Q

What is an organ system?

A

Organs that are working together to form a system.

36
Q

What is mitosis used for?

A

Growth, tissue repair, asexual reproduction.

37
Q

What is mitosis used for?

A

Growth
replacing worn out cells
repairing damaged tissues
reproduction asexually