Unit 7 Flashcards

Unit 7

1
Q

What is a genome?

A

the complete complement of an organism’s genetic material, including the noncoding regions of DNA

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2
Q

What are chromosomes?

A

discrete sections of the DNA molecule that carry a specific assemblage of genes

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3
Q

Section of a chromosome that codes for a specific protein

A

gene

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4
Q

Chromosome that are inherited from different parents that carry the same assemblage of genes

A

homogulous chromosomes

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5
Q

What is chromatin?

A

loosely arranged DNA that is accessible to cellular machinery for protein construction

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6
Q

Chromosomes that consist of DNA that is bound to proteins and inaccessible to cellular machinery; used to move chromosomes within the cell and inactivate genes

A

condensed chromosome

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7
Q

What determines the length of a chromosome?

A

the number of coding and non-coding regions on the chromosome, this varies siginificantly between chromosomes

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8
Q

Consists of a single copy of each gene, when condensed, the chromosome is constricted near the middle at the centromere

A

pre-replication chromosome

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9
Q

Region of highly condensed DNA; genes here are inaccessible for replication

A

centromere

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10
Q

Consists of two copies of each gene distrubuted across two chromatids

A

post-replication chromosome

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11
Q

Each consists of an “arm” and a “leg” that are connected at the centromere; are attached to eachother by cohesion proteins

A

chromatid

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12
Q

What is the cell cycle?

A

natural process of cell growth and replication

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13
Q

Phase in which DNA and organelles are replicated in preparation for division

A

interphase

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14
Q

Cell growth and organelle replication

A

G1 phase

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15
Q

DNA replication/synthesis

A

S phase

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16
Q

Cell growth and replication

A

G2 phase

17
Q

Division of the nucleus; equitable distribution of DNA between two daughter nuclei

A

mitosis

18
Q

Division of the cell

A

cytokenesis

19
Q

Initial phase of mitosis

A

prophase

20
Q

What occurs during prophase?

A

chromatin fibers condense to form tightly packaged chromosomes, nuclear envelope fragments and dissolves, mitotic spindle begins to form, the centrioles are duplicated in the G phases of interphase, so each cell in mitosis has 2

21
Q

What is the second phase of mitosis?

A

metaphase

22
Q

What occurs during metaphase?

A

centrioles have completely migrated to opposite poles of the cell, mitotic spindle is complete, each chromosome is attached to both centrioles, chromosomes have migrated to the center of the cell

23
Q

What is the third phase of mitosis?

A

anaphase

24
Q

What occurs during anaphase?

A

cohesion proteins are cleared, and sister chromatids become independent. liberated chromatids become true chromosomes and migrate to opposite poles of the cell toward centrioles

25
Q

What is the final stage of mitosis?

A

telophase

26
Q

What occurs during telophase?

A

microtubules detach from chromosomes, nuclear envelope reforms around chromosomes, chromosomes unwind and return to chromatin format

27
Q

What is cytokenesis?

A

division of the cell

28
Q

Why is the cell cycle closely regulated?

A

to avoid aberrant and uncontrolled growth of tissues; consists of a series of cyclically available molecules and distinct checkpoints

29
Q

What are checkpoints?

A

discrete times in the cell cycle where specific criteria must be met before the cell continues to grow and divide

30
Q

cells assess the replication of organelles and cytosol organelles; for mammilian cells, if it passes this checkpoint, it will likely pass the rest

A

G1 checkpoint

31
Q

cells assess the replication of all organelles, proteins, and DNA

A

G2 checkpoint

32
Q

Occurs during metaphase; cells assess the position of chromosomes along the metaphase plate

A

M checkpoint

33
Q

What happens to the cells that do not pass?

A

move into arrested development of G0

34
Q

Cells will not divide if the cell density is too ___.

A

high

35
Q

In which stage of the cell cycle is DNA replicated?

A

S phase

36
Q

In which stage of mitosis do the chromosomes align at the center of the cell?

A

metaphase

37
Q

In which stage of mitosis does the nuclear envelope dissolve?

A

prophase

38
Q

In which stage of mitosis do sister chromatids migrate to opposite poles of the cell?

A

anaphase