C8 - Cell Replication Flashcards

1
Q

What is DNA?

A

The way living things pass on traits (hair colour, eye colour, height)

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2
Q

What is a chromosome?

A

A single DNA molecule containing many genes

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3
Q

What are genes?

A

Sections of DNA that code for proteins

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4
Q

What are homologous chromosomes?

A

2 molecules of DNA that contain the same genes (1 from each parent)

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5
Q

What is the Cell Cycle?

A

The cycle of creating new cells that all cells exist in - all cells come from pre-existing cells through the completion of this cycle

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6
Q

What are the different phases of the cell cycle?

A

G1, S, G2, M

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7
Q

In eukaryotic cells, what are the two major stages of the cell cycle?

A

Interphase and mitotic phase

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8
Q

What is interphase?

A

When the cell grows and copies its DNA

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9
Q

What is the mitotic phase?

A

The cell separates it’s DNA into 2 sets and divides its cytoplasm (cytokinesis) forming two new cells

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10
Q

What is cytokinesis?

A

When a cell divides its cytoplasm to form 2 new cells

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11
Q

Which stages of the Cell Cycle does interphase cover?

A

G1, S and G2

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12
Q

What is the G1 phase?

A

The first gap phase, the cell grows physically larger, copes organelles and makes biomolecules important for later steps

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13
Q

What is the S phase?

A

Synthesis, where DNA replication occurs in the nucleus, and the centrosome (a microtubule-organising structure for seperating DNA) is duplicated

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14
Q

What is the G2 phase?

A

The second gap phase, where the cell grows more, and makes proteins and organelles. This phase ends when mitosis begins

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15
Q

What is the M phase?

A

Mitosis, used for growth, repair or asexual reproduction

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16
Q

Does mitosis make diploid or haploid cells?

A

Diploid cells

17
Q

Is mitosis cloning?

18
Q

Outline the process of mitosis

A

Interphase: DNA replicates, as do organelles
Prophase: Chromosomes condense and become visible and the nucleus disappears
Metaphase: The spindle fibers have descended and attached to the centromeres and lined the chromosomes up on the cell equator (or metaphase plate)
Anaphase: The spindle fibers pull the chromosomes apart and also push the cells poles apart
Telophase: The chromosomes form chromatin again, and the contractile ring pulls the cell membrane together until the cell divides
Cytokinesis: When the cell divides into two new daughter cells

19
Q

What is meiosis?

A

The process of creating four genetically unique daughter cells with half the number of chromosomes

20
Q

When is meiosis used?

A

Sexual reproduction only

21
Q

Does meiosis create diploid or haploid cells?

A

Haploid (one chromosome)

22
Q

Outline the first stage of meiosis

A

Interphase: DNA and organelles replicates
Prophase 1: Homologous chromosomes pair up and ‘stick’ via synapsis, then segments of sister chromosomes switch in a process known as crossing over
Metaphase 1: The pairs all line up in the centre of the cell and are held in place with spindle fibers (independent assortment occurs here)
Anaphase 1: The pairs separate and two chromatids move towards each pole of the cell
Telophase 1: The two cells separate and cytokinesis occurs

23
Q

Outline the second stage of meiosis

A

Prophase 2: nucleus of intermediary daughter cells disappear and the centrosomes begin to move towards poles
Metaphase 2: Chromosomes lined up in the centre of the cell
Anaphase 2: Replicated chromosomes split
Telophase 2: Cells divide into 4 individual daughter cells (forming gametes)

24
Q

What is independent assortment?

A

Chromosomes go into each new cell randomly, so any mixed chromosome ( chromosome with changed alleles) can go into any of the four daughter cells, creating even more variation

25
How do prokaryotes reproduce?
Via mitotic binary fission
26
What is fragmentation?
One part splits into pieces and each develops into a new organism (flatworms)
27
What is parthenogenesis?
When female produced eggs hatch without fertilisation (worker bees)
28
What are the different types of twins?
Fraternal: twin eggs fertilised by 2 sperm (different genetics) Identical: fertilised egg splits into 2 (same genetics)
29