the nucleus

Question 1

nucleoplasm

Answer 1

similar in composition to cytoplasm
gel like material containing water, proteins, nucleotides, and other dissolved substances

Question 2

nuclear envelope structure

Answer 2

-made up of 2 unit membranes separated by a perinuclear space
-outer membrane continuous w RER and has ribosomes
-inner membrane supported by nuclear lamina, formed lamins and associated proteins

Question 3

nuclear pores

Answer 3

areas of continuity between outer and inner membranes

Question 4

function of nuclear pore complex and associated w what proteins

Answer 4

regulates passage of molecules between nucleus and cytoplasm
associated w nucleoporins

Question 5

chromatin

Answer 5

material which forms chromosomes, but in a uncoiled state

Question 6

what are the 2 configurations of chromatin

Answer 6

heterochromatin - dense, clumped, often located at periphery of nucleus
euchromatin - finely dispersed, granular, uncoiled, actively transcribing

Question 7

nucleosome form and function

Answer 7

-group of 8 histones with coiled double loop of DNA around it
-helps to compact chromatin

Question 8

chromosome structure

Answer 8

2 chromatids joined by centromere

Question 9

what is telomere and why is it important

Answer 9

-region located at end of chromosome
-telomere shortens w each cell division (lifespan of a cell is limited by telomere length)

Question 10

telomerase

Answer 10

adds a repeated nucleotide sequence to the end of the telomere in malignant cells

Question 11

humans have how many chromosomes, how many pairs of homologous chromosomes (how many pairs of autosomes and sex chromosomes), what are female and male sex chromosomes

Answer 11

46 chromosomes
23 pairs of homologous chromosomes
22 pairs of autosomes
1 pair of sex chromosomes
females (XX), males (XY)

Question 12

sex chromatin or barr body

Answer 12

inactive chromosome / mass of condensed chromatin

Question 13

somatic cells are haploid or diploid
gametes are haploid or diploid

Answer 13

somatic - diploid - 2n chromosomes
gametes - haploid n chromosomes

Question 14

nucleolus structure

Answer 14

a small dense spherical structure in the nucleus of a cell during interphase

roughly spherical in shape
non-membraneou
highly basophilic
sometimes 2 nucleoli in a single nucleus

Question 15

nucleolus are present in the nucleus of cells that produce what

Answer 15

protein-producing cells

Question 16

nucleolus composed of what

Answer 16

chromatin containing genes for rRNA
RNA polymerase 1
ribosomes

Question 17

what do cohesins do

Answer 17

hold the chromatids together at the centromere in anaphase

Question 18

how long does mitosis last

Answer 18

about 1hr

Question 19

how long does G1 last

Answer 19

9-12 hr

Question 20

what occurs in G1 and what are the 2 checkpoints

Answer 20

cells gather nutrients, synthesize RNA and proteins necessary for DNA synthesis

restriction checkpoint - monitors cell’s size, physiological state and interactions w extracellular matrix

DNA damage checkpoint - if DNA is damaged, cell might undergo apoptosis

Question 21

how long does S phase last

Answer 21

7.5-10 hrs

Question 22

what happens in S phase and what checkpoint

Answer 22

DNA is replicated - new chromatids are formed

DNA damage checkpoint - monitors the quality of the replicating DNA

Question 23

how long does G2 last

Answer 23

3.5-4.5 hrs

Question 24

what happens in G2 and what checkpoints

Answer 24

cell growth and reorganization of organelles in preparation for mitosis

-DNA damage checkpoint
-unreplicated DNA checkpoint - prevents progression to M phase until replication of DNA is complete

Question 25

in what phase would a cell switch to G0

Answer 25

during G1