Introduction, Chromosome Structure, Mitosis (Lec 1)

Question 1

Oculocutaneous albinism type 2 is due to a defect in what gene on chromosome 15?

Answer 1

OCA

Question 2

What did Archibald Garrod discover?

Answer 2

Alkaptonuria

Question 3

What is a genome?

Answer 3

set of genetic instructions for any organism

Question 4

Pangenesis theory stated what?

Answer 4

specific particles (gemmules) carry information from various parts of the body to reproductive organs, from which they are passed to the embryo at the moment of conception

Question 5

Inheritance of Acquire Characteristics theory stated what?

Answer 5

traits acquired in a person’s lifetime become incorporated into that person’s hereditary information and are passed on to offspring

note: made famous by Lamarck

Question 6

What did the Blending Inheritance theory state?

Answer 6

offspring are a blend of parental traits; genetic material itself blends; once blended, genetic differences cannot be separated out in future generations

Question 7

What are some common characteristics of model organisms for genetic testing?

Answer 7

short generation time, production of numerous progeny, the ability to carry out controlled genetic crosses, the ability to be reared in a laboratory environment, the availability of numerous genetic variants, an accumulated body of knowledge about their genetic systems

Question 8

What are alleles?

Answer 8

multiple forms of a gene

Question 9

How do prokaryotes reproduce?

Answer 9

a process that is called binary fission. The DNA in such cells is contained in a single circular chromosome called a plasmid within the cytoplasm. The reproductive process starts with the replication of the chromosome. The new chromosome attaches itself to the plasma membrane and the two chromosomes migrate to opposite ends of the cell. The plasma membrane in the middle of the cell grows inward until it closes to separate the cell into two compartments, each with a full complement of genetic material. The cell then “fissions” at the center, forming two new daughter cells.

Question 10

What are some characteristics of prokaryotes?

Answer 10

Nucleus is absent, single circular DNA molecule, no histones in eubacteria (some in archaea), membrane-bound organelles are absent, cytoskeleton is absent

Question 11

What are some characteristics of eukaryotes?

Answer 11

membrane-bound nucleus is present, multiple linear DNA molecules, histones pack DNA molecules, membrane-bound organelles are present, cytoskeleton is present

Question 12

DNA + Histones = ?

Answer 12

chromatin

Question 13

True or False?

Eukaryotic DNA must separate from histones before genetic information can be accessed

Answer 13

true

Question 14

What is the function of the centromere, in regards to eukaryote chromosome structure?

Answer 14

serves as the attachment point for spindle microtubules, used for chromosome classification

Question 15

What is the function of the centromere?

Answer 15

location where the kinetochore forms and the spindle microtubules attach

Question 16

What are telomeres and what do they do?

Answer 16

natural ends of a chromosome, provide chromosome stability, may limit cell division

Question 17

What is telomerase?

Answer 17

Enzyme that adds DNA sequences to the chromosome so telomeres do not lose length

Question 18

What are the major functions of mitosis?

Answer 18

stockpile of cells for embryogenesis, provides mechanism for the replacement of damaged or worn-out cells

Question 19

What happens in the S phase of the cell cycle?

Answer 19

DNA synthesis, chromosome replication, G-1(S)-cyclins degraded, inactive cdc2 kinase, B(M)-cyclin concentration begins to increase toward end of S phase, take about 7 hours

Question 20

What happens in the G2 phase of the cell cycle?

Answer 20

further preparations for mitotic division, B(M)-cyclins bind to cdc2 kinase, activated MPF leads to activities necessary for mitosis, takes about 2 hours

Question 21

What happens in the M phase of the cell cycle?

Answer 21

Mitosis, B(M)-cyclin is degraded toward end of phase, cdc2 kinases becomes inactivated, takes about 0.7 hours

Question 22

What happens in interphase of mitosis?

Answer 22

chromosomes uncoiled

Question 23

What happens in prophase of mitosis?

Answer 23

centrioles move to opposite poles, spindle apparatus is organized, nuclear membrane begins to disintegrate, chromosomes become condensed

Question 24

What happens in metaphase of mitosis?

Answer 24

chromosomes are located at center of cell along equatorial plate, spindle fibers are attached to kinetochores, centromeres divide at end of metaphase, chromosome number has doubled

Question 25

What happens in anaphase of mitosis?

Answer 25

daughter chromatids separate

Question 26

What happens in telophase of mitosis?

Answer 26

chromosomes begin to uncoil, nuclear membranes reform, cytokinesis usually occurs and two daughter cells are separated

Question 27

What happens in the G1 phase of the cell cycle?

Answer 27

first gap/growth phase, concentration of G-1(S)-cyclins increases, G-1-cyclin binds to inactive cdc2 kinase, MPF is activated at end of this phase and leads to activities needed for DNA synthesis, highly variable with regard to time

Question 28

What happens in G0 phase of the cell cycle?

Answer 28

condition of a cell that has been taken out of the classical cell cycle

Question 29

What are embryonic cells?

Answer 29

cells that proceed immediately to the next cell cycle with little time in the G1 phase; do not grow or differentiate

Question 30

What are Labile cells?

Answer 30

cells that spend more time in the G1 stag and grow and become differentiated; ex: epithelial cells, hematopoietic cells

Question 31

Non-dividing cells are permanently locked in what phase of the cell cycle?

Answer 31

G1 phase; ex: skeletal muscle cells, cardiac muscle cells, neurons

Question 32

What is karyokinesis?

Answer 32

physical division of nuclear material

Question 33

What is cytokinesis?

Answer 33

physical division of cytoplasmic material

Question 34

What is endomitosis?

Answer 34

karyokinesis is not followed by cytokinesis which results in an increase in ploidy (increase in complete sets of chromosomes)