Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIO 102 > Topic 4 (pre-exam) > Flashcards

Topic 4 (pre-exam) Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

how often does the cell cycle occur, and how long does each stage last?

A

once approximately every 24 hours (circadian rhythms)

interphase - G1: 11 hours; S: 8 hours; G2: 4 hours
mitosis - 1 hour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

role of S phase and G2 phase in the cell cycle

A

prepare the cell for division (mitosis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the best way to distinguish living/nonliving matter?

A

cell division; continuity of life based on the reproduction of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

cell division in unicellular organisms

A

cell division is reproduction; division of one cell replicates the entire organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

purpose of cell division in multicellular organisms

A

needed for:

  • development of a fertilized cell
  • growth
  • repair (i.e. tissue renewal)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the result of mitotic vs meiotic cell division?

A

mitotic: daughter cells with identical genetic info (DNA) and 2 sets of chromosomes
meiotic: nonidentical daughter cells (gametes aka sperm and egg cells) with only 1 set of chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

genome

A

all of the DNA in a cell (including in mitochondria and/or chloroplasts)

*can consist of a single DNA molecule (prokaryotes) or a number of DNA molecules eukaryotes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

function and significance of chromosomes

A

DNA is condensed and packaged into chromosomes (with proteins) during prophase

*every eukaryotic species has a characteristic number of chromosomes in each cell nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

somatic cells vs gametes

A

somatic cells: non-reproductive; 2 sets of chromosomes

gametes: reproductive; half the chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

chromatin

A

complex of DNA and protein that condenses into chromosomes during cell division; makes up eukaryotic chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what occurs in preparation for cell divison?

A

DNA is replicated and chromosomes condense

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

sister chromatids

A

the 2 identical copies of a chromosome after it’s been duplicated that separate during cell division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

centromere

A

the narrow waist of a duplicated chromosome, tightly attaches sister chromatids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

two phases of eukaryotic cell division

A

mitosis - division of nucleus

cytokinesis - division of cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

historical breakthrough in observing the cell cycle

A

Walter Flemming developed dyes to observe chromosomes and see their change in form, called the “father of cytogenics”

*various staining techniques today to observe chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

two parts of the cell cycle and their functions:

A

Mitotic (M) phase - mitosis and cytokinesis

Interphase - cell growth and copying of chromosomes in preparation for cell division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

phases of mitosis

A

prophase, prometaphase, metaphase, anaphase, telophase

  • cytokinesis underway by late telophase
  • process is still a continuum!!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

prophase

A

assembly of mitotic spindle

  • DNA condenses into chromosomes
  • nuclear envelope disappears
  • centrosome (outside of nuclear envelope) replicates in 2; migrates to opposite ends of cell
  • spindle microtubules are assembled and begin to grow out of centrosomes
  • asters extends from each centrosome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

centrosomes

A
  • both create and control microtubules

- discovered by Walther Flemming; only in animal cells (unknown where plant microtubules come from)

20
Q

mitotic spindle

A

made of up centrosomes, spindle microtubules, and asters

21
Q

asters

A

radial array of short microtubules extending from each centrosome

22
Q

types of microtubules

A

spindle microtubules

  • kinetochore: attach to kinetochore of chromosomes during prometaphase to pull chromosomes apart during anaphase
  • nonkinetochore: overlap and push against eachother during telophase to elongate cell

other microtubules
- asters: short microtubules that anchor spindle posts to cell membrane

23
Q

prometaphase

A

spindle microtubules attach to kinetochores of chromosomes and begin to move them

24
Q

kinetochores

A

complex of proteins associated with the centromere of chromosomes where spindle fibers attach

25
Q

metaphase

A

chromosomes lined up at metaphase plate (cell equator) midway between spindle’s 2 poles

26
Q

anaphase

A

sister chromatids separate and move along kinetochore microtubules towards opposite ends of cell
- microtubules shorten by depolymerizing at kinetochore ends

27
Q

telophase

A

nonkinetochore microtubules from opposite poles overlap and push against each other, elongating cell
- genetically identical daughter nuclei form at opposite ends of cell

28
Q

how did scientists learn how kinetochores depolymerize?

A
  • scientists used a pig kidney cell in early anaphase
  • spindle microtubules dyed and part was lasered to remove fluorescence
  • they monitored change in length on either side of the mark as the chromosomes moved towards the poles
  • microtubules on kinetochore side shortened, so depolymerization happens at kinetochore end
29
Q

cytokinesis (plants vs animals)

A
  • in animal cells: cleavage furrow forms

- in plant cells: more rigid, so a cell plate forms to divide them

30
Q

binary fission

A
  • method of prokaryote reproduction

- chromosome replicates and 2 daughter chromosomes actively more apart

31
Q

evolution of mitosis

A
  • mitosis evolved form binary fission because prokaryotes existed before eukaryotes
  • some protists exhibit “in-between” types of cell division
32
Q

what is the molecular control system?

A

chemical signals in the cytoplasm cause the frequency of cell division to vary with cell type

33
Q

evidence for regulation of cell division coming from the cytoplasm

A
  • mammalian cells at different phases of the cell cycle were fused to form a single cell with 2 nuclei
  • when cells in S and G1 fused, nucleus of G1 cell immediately entered S phase and DNA synthesized
  • when cells in M and G1 fused, nucleus of G1 cell began mitosis (spindle formed and chromatin condensed) even though chromosomes had not been duplicated
34
Q

cell cycle control system

A

directs the sequential events in the cell cycle (like a clock)

  • both internal and external controls
  • specific checkpoints control where cell cycle stops until go-ahead signal received
35
Q

important checkpoints in cell cycle control system

A

most important: G1 checkpoint
- cells that get go-ahead will complete other phases and divide; cells that don’t get go-ahead signal will exit the cycle and switch into a non-dividing state called G0 phase

G2 checkpoint
- gives ok for cell division; right before M phase

36
Q

G0 phase

A

non-dividing state if no go-ahead signal is received at the G1 checkpoint

37
Q

regulatory proteins involved in cell cycle control

A

cyclins and cyclin-dependent kinases (Cdks)

- actively fluctuate levels during the cell cycle

38
Q

role of MPF

A

MPF (maturation-promoting-factor) is a cyclin-Cdk complex that gives the cell the go-ahead past the G2 checkpoint, stimulating the mitotic (M) phase
- once mitosis completed, cyclins degrade from MPF

39
Q

equation for determining concentrations

A

C1V1 = C2V2

40
Q

examples of internal cell signaling

A

when kinetochores not attached to the spindle, a signal is sent to delay anaphase

41
Q

examples of external cell signaling relating to mitosis

A

growth factors - proteins from some cells stimulate other cells to divide
- platelet-derived growth factor (PDGF) - stimulates division of human fibroblast cells

density-dependent inhibition - crowded cells stop dividing

42
Q

anchorage dependence

A

cells must be attached to a substratum in order to divide (most animal cells)
*cancer cells often don’t have this

43
Q

characteristics of cancer cells

A
  • no density-dependent inhibition nor anchorage dependence
  • don’t respond to cell cycle control mechanisms
  • may not need growth factors to divide (make their own growth factor, convey growth signal without factor, or have abnormal control system)
44
Q

transformation

A

process by which normal cells transformed to cancerous cells

45
Q

what do cancer cells do? why are they dangerous?

A

form tumors - masses of abnormal cells within otherwise normal tissue

***can invade healthy tissue (disrupting functions of organs) and take resources away from the cell

BIO 102 (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions