The Nucleus

Question 1

how many membranes does the nucleus have

Answer 1

2

Question 2

what is the name for the dense fibrillar network inside the nucleus of most cells that provides mechanical support and regulates important cellular events such as DNA replication and cell division

Answer 2

nuclear lamina

Question 3

what is chromatin composed of

Answer 3

complex of five structural proteins and DNA

Question 4

when is chromatin movement active

Answer 4

when there is genetic activity such as gene turning on

Question 5

how many chromosomes does the human cell contain

Answer 5

46

Question 6

how many autosomes or homogenous pairs of chromosomes do humans have

Answer 6

22

Question 7

what is the diploid number of somatic cells

Answer 7

2n

Question 8

what cells have a haploid number of chromosomes

Answer 8

sperm and ovarian cells

Question 9

what does the lowercase d stand for in mitosis

Answer 9

DNA content

Question 10

how many base pairs are present in the human genome

Answer 10

more than 3 million DNA base pairs

Question 11

what are the four DNA bases

Answer 11

adenine
thymine
guanine
cytosine

Question 12

what are the four phases of the cell cycle

Answer 12

Gap 1 (G1)
synthesis
Gap 2 (G2)
mitosis

Question 13

what does G0 represent in the cell cycle

Answer 13

phase where the cell exits the cell cycle

Question 14

at what phase of the cell cycle does the cell divide

Answer 14

mitosis

Question 15

what is the longest phase of the cell cycle

Answer 15

G1 or growth phase

Question 16

what happens to the chromosomes during the S phase of the cell cycle

Answer 16

each of the 46 chromosomes are duplicated

Question 17

during mitosis, one nucleus will become how many nuclei with identical genetic information

Answer 17

2 nuclei

Question 18

what happens to the nuclear membrane during prophase

Answer 18

it disappears

Question 19

when do the 2 nuclei of mitosis and cytoplasm split into 2 cells

Answer 19

during cytokinesis

Question 20

what types of cell undergo meiosis, forming with a haploid number

Answer 20

gametes

Question 21

what are the two major check points for cell regulation during the cell cycle

Answer 21

between G1 and S
between G2 and M

Question 22

what is considered the most critical check point in the cell cycle that can result in what is referred to as a mitotic catastrophe that can lead to cell death or tumor development

Answer 22

between G1 and S

Question 23

what controls the cell cycle checkpoints

Answer 23

cyclin dependent kinases

Question 24

what protein forms from the cyclin kinase complex, is produced by a tumor suppressor gene, and when defective can lead to retinoblastoma

Answer 24

RB

Question 25

what protein binds to DNA directly to produce proteins that block the progression of the cell cycle

Answer 25

P35 known as the guardian of the genome

Question 26

what protein functions to inhibit CDK so it won't be able to activate DNA replication or mitosis, but does not lead to cancer when defective

Answer 26

P21

Question 27

defective suppressor genes often lead to what

Answer 27

neoplastic growth

Question 28

what does the number of mitotic metaphases indicate

Answer 28

the mitotic activity of the cell

Question 29

what are the 3 major cell population classifications related to cell mitotic activity

Answer 29

static cell populations stable cell populations cell renewal populations

Question 30

what 3 types of cells that are considered static or no longer divide

Answer 30

CNS cells skeletal muscle cells cardiac muscle cells

Question 31

what 4 cell types are considered stable or mitotically active during injury

Answer 31

periosteal and perichondrial cells smooth muscle cells endothelial cells of the blood vessels fibroblasts of the connective tissue

Question 32

what are the 3 examples of slow renewing cells

Answer 32

smooth muscle cells of most hollow organs fibroblasts of the uterine wall epithelial cells of the lens of the eye

Question 33

what are 3 examples of fast renewing cells

Answer 33

blood cells epithelial and dermal fibroblasts of the skin epithelial and sub epithelial fibroblasts of mucosal lining of the GI tract

Question 34

how many cells are produced in the human body per day

Answer 34

100 billion

Question 35

what is the frequency of somatic cell mutations

Answer 35

1 every million replications of a cell

Question 36

what are some common features of neoplastic cells

Answer 36

high mitotic rates mass forming failure to activate apoptosis mutations of future DNA metastasis invasion

Question 37

what are some microscopic features suggestive of malignancy

Answer 37

large, variably sized nuclei increased cell division disorganized cell pattern variation of cell size and shape loss of normal features

Question 38

the T antigen of simian virus (SV40) protein that binds to pRb interferes with the specific checkpoints in the cell cycle that have been fond to be involved in which 3 tumors

Answer 38

mesothelioma osteosarcoma ependymoma

Question 39

reserve stem cells may be re-activated into the cell cycle in what 3 circumstances

Answer 39

normal wound healing radiation organ regeneration

Question 40

what happens if the damage to tissue is extensive enough to cause the reserve stem cells to die

Answer 40

no healing or regeneration will occur

Question 41

what are the three germs layers that can result from an embryonic stem cell

Answer 41

ectoderm mesoderm endoderm

Question 42

what are the 3 major differences between adult stem cells and embryonic stem cells

Answer 42

adult cells have determined type adult are difficult to culture in-vitro can only be autologously transplanted

Question 43

homeostasis is critical in maintaining a balance between what

Answer 43

cell accumulation and cell death

Question 44

how does cancer impact the balance of homeostasis

Answer 44

it causes cell accumulation

Question 45

how does ischemic injury impact the balance of homeostasis

Answer 45

it causes cell death

Question 46

what type of injury may result in necrosis

Answer 46

hypothermia hypoxia radiation low pH cell trauma

Question 47

what type of 2 immune cells can destroy cancer transformed cells or cells infected with a viral pathogen

Answer 47

cytotoxic T lymphocytes natural killer (NK) cells

Question 48

what factors inhibit apoptosis

Answer 48

growth factors hormones like androgens and estrogen neutral amino acids zinc interactions with extracellular matrix proteins several cellular and viral proteins act as a cascade inhibitor