Bio Chapter 10

Question 1

Diploid (2n)

Answer 1

Carries 2 sets of genetic information, somatic cells (anything other than sperm and eggs)

Question 2

Haploid (n)

Answer 2

Carries 1 set of genetic information, gamete (reproductive) cells

Question 3

DNA organization in eukaryotes

Answer 3

DNA double helix
DNA wrapped around a histone - group of proteins
Nucleosomes (groups of histones) are coiled into a chromatin fiber
Further condensation of chromatin
Duplicated chromosome
*Eukaryotic chromosomes are much larger and more complex than prokaryotes

Question 4

Genome

Answer 4

All the genes in one package, all the genetic information that defines an organism

Question 5

DNA repair genes

Answer 5

Not repairing damage to control of proliferation, differentiation or apoptosis
Repair mechanisms check DNA and repair genes

Question 6

Oncogenes

Answer 6

A normal cellular gene that is altered or deregulated in a way that directly contributes to the malignant transformation
Proto-oncogene is the gene before it undergoes mutations (potential of becoming cancer gene)

Question 7

Tumor supressor genes

Answer 7

Encode negative regulators of cell proliferation (splitting) or survival
Loss of function to the gene allows for tumor formation

Question 8

Sister chromatids

Answer 8

A chromosome usually consists of 2 sister chromatids
During cell division, the 2 sister chromatids of each chromosome are duplicated and then separated into 2 nuclei

Question 9

Cohesion

Answer 9

Proteins that join 2-sister chromatids to one another, ring-like cells
During anaphase, cohesions are cleaved and sister chromatids separate
They move along kinetochore microtubules to opposite ends of the cell

Question 10

Phases of the cell cycle

Answer 10

Mitotic (M) phase - includes mitosis (nuclear division) or cytokinesis (cytoplasmic division)
Interphase - cell growth and copying of chromosomes in preparation for cell division

Question 11

Phases of interphase

Answer 11

Most of the cell’s time is spent here (90% of the cell cycle)
G1 phase (gap phase - cell growth)
S phase (synthesis - the cells replicates DNA here, number of molecules double but number of chromosomes stays the same, chromosomes are duplicated ONLY during S phase
G2 phase (gap phase - cell growth)

Question 12

Cleavage furrow

Answer 12

Animal cells form a cleavage furrow
A contractile ring made from actin and myosin pinches the cell in two
As cytokinesis progresses, the contractile ring becomes smaller
It will disassemble completely once the cell has finished dividing in two

Question 13

Stages of mitosis

Answer 13

Prophase
Prometaphase
Metaphase
Anaphase
Telophase

Question 14

Prophase

Answer 14

The chromosomes were duplicated by the time prophase starts
Chromosomes condense
Mitotic spindle assembles between centrosomes
Nucleolus disappears

Question 15

Prometaphase

Answer 15

Starts with breakdown of nuclear envelope
Chromosomes attach to spindle microtubules via kinetochores
Chromosomes start to move toward center of cell
Centrosomes (spindle pole) move to opposite poles of the cell

Question 16

Metaphase

Answer 16

Chromosomes are aligned at the equator of the spindle (midway between spindle poles)
Kinetochore microtubules on each sister chromatid attach to opposite poles of the spindle

Question 17

Anaphase

Answer 17

Sister chromatids separate
Pulled to opposite poles
Kinetochore microtubules get shorter and spindle poles move apart
Ends when the groups of chromatids have arrived at opposite ends of the cell

Question 18

Telophase

Answer 18

Chromosome sets arrive at poles of spindle
New nuclear envelope forms around each set of chromosomes
End of mitosis

Question 19

G1 checkpoint

Answer 19

If the cell doesn’t receive a go-ahead signal, it exits the cycle and switches to a non-dividing state called the G0 phase

Question 20

M checkpoint

Answer 20

Cells will not begin anaphase until all chromosomes are properly attached to the spindle at the metaphase plate
Ensures that daughter cells have the correct number of chromosomes
Stop signal without full chromosomes attachment
Go-ahead signal with full chromosomes attachment

Question 21

Binary fission in bacteria

Answer 21

Prokaryotes reproduce by binary fission (NO MITOSIS)
The chromosome replicates - starts at origin of replication
2 daughter chromosomes actively move apart
Plasma membrane pinches inward dividing cell in two

Question 22

What are chromosomes composed of?

Answer 22

DNA and proteins

Question 23

Be able to calculate number of chromosomes in different parts of cell cycle