1.6 Cell devision Flashcards Preview

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Flashcards in 1.6 Cell devision Deck (16)
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1
Q

Two main phases of the cell cycle

A

Interphase

M phase

2
Q

Interphase

A

G1 – First intermediate gap stage in which the cell grows and prepares for DNA replication
S – Synthesis stage in which DNA is replicated
G2 – Second intermediate gap stage in which the cell finishes growing and prepares for cell division

3
Q

M phase

A

Mitosis

Cytokinesis

4
Q

Mitosis

A

Nuclear division, whereby DNA (as condensed chromosomes) is separated into two identical nuclei

5
Q

Cytokinesis

A

Cytoplasmic division, whereby cellular contents are segregated and the cell splits into two

6
Q

Processes that occur in the interphase

A
DNA replication 
Organelle duplication 
Cell growth 
Transcription / translation 
Obtain nutrients
Respiration (cellular)
7
Q

Features of chromatin

A

loosely packed
DNA is accessible to transcriptional machinery and so genetic information can be translated
in all non-dividing cells and throughout the process of interphase

8
Q

Features of chromosome

A

packaged into a tightly wound and condensed chromosome
DNA is able to be easily segregated however is inaccessible to transcriptional machinery
during the process of mitosis (condense in prophase, decondense in telophase)

9
Q

Chromosome vs Chromatid

A

A chromosome is the condensed form of DNA which is visible during mitosis (via microscopy)

As the DNA is replicated during the S phase of interphase, the chromosome will initially contain two identical DNA strands

These genetically identical strands are called sister chromatids and are held together by a central region called the centromere

When these chromatids separate during mitosis, they become independent chromosomes, each made of a single DNA strand

10
Q

Mitosis

A

the process of nuclear division, whereby duplicated DNA molecules are arranged into two separate nuclei

11
Q

Four stages of mitosis

A

prophase, metaphase, anaphase, telophase

12
Q

Before mitosis

A

Interphase:

DNA is present as uncondensed chromatin
DNA is contained within a nucleus
Centrosomes and other organelles have been duplicated
Cell is enlarged in preparation for division

13
Q

Prophase

A

spindle microtubules are growing
chromosomes are becoming shorter and fatter by supercoiling
each chromosome consists fo two identical chromatids formed by DNA replication in interphase and held together by a centromere
spindle microtubules extend from each pole to the equator

14
Q

Metaphase

A

the nuclear membrane has broken down and chromosomes have moved to the equator
spindle microtubules from both poles are attached to each centromere, on opposite sides

15
Q

Anaphase

A

the centromeres divide to allow sister chromatids to separate
spindle microtubules pull the genetically identical chromosomes to opposite poles

16
Q

Telophase

A

all chromosomes have reached the poles and nuclear membranes form around them
spindle microtubules break down
chromosomes uncoil and are no longer visible
the cell divides with genetically identical nuclei