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Biology 101 > M2 Lecture 15,18, part of 20 > Flashcards

M2 Lecture 15,18, part of 20 Flashcards

1
Q
  • What are some functions/roles of actively dividing cells?
A

o Increasing population of single-celled organism
o Growth of multicellular tissue
o Asexual reproduction + replacement of cells lost to wear and tear

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2
Q

7.2 The Cell Cycle in Prokaryotic Organisms

In the 3-period cycle newly formed prok. Cell must:

A

 Increase in size
 Replicate circular chromosome
 Move each of two daughter chromosomes into progeny cell during cell division

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3
Q

7.2 The Cell Cycle in Prokaryotic Organisms

What is binary fission?

A

: division into two parts

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4
Q

7.2 The Cell Cycle in Prokaryotic Organisms

Exlapin the 3 periods of the 3 period cell cycle:

A

o B period:
 Daughter cells are formed, they grow during B period, initiate DNA synthesis
 When nutrients = abundant, prokaryotic cells = no need for B period (b/c can grow quickly enough for it to divide cytoplasm as soon as DNA replication is complete + chromosomes are separated
o C period:
 Once chromosomes = replicated, they separate to opposite ends of cell (poles)
o D period:
 Membrane pinches together between them and 2 daughter cells are formed via binary fission

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5
Q
  1. 2 a Replication occupies most of the cell cycle in rapidly dividing prokaryotic cells
    - Bacteria + Archaea: use DNA as what?
A

… as hereditary info then packaged into circular chromosome

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6
Q

7.2 a Replication occupies most of the cell cycle in rapidly dividing prokaryotic cells

Where are chromosomes located, what are they?

A

o Compacted in central region called nucleoid

  • A chromosome is a long DNA molecule with part or all of the genetic material of an organism.
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7
Q
  1. 2 b Replicated chromosomes are distributed actively to the daughter cells in binary fission
    - Bacterial chromosomes separate ____ to membrane dynamics and is linked to DNA replication
A

independantly

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8
Q

7.2 b Replicated chromosomes are distributed actively to the daughter cells in binary fission

What is the Origin of replication (ori)?

A

o specific region in middle of cell where replication of bacterial chromosomes begins @ specific region of DNA sequence

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9
Q

7.2 b Replicated chromosomes are distributed actively to the daughter cells in binary fission

Where is Ori located?

A

o Ori = located where enzymes for DNA replicated are located

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10
Q

7.2 b Replicated chromosomes are distributed actively to the daughter cells in binary fission

o Completion of ori duplication results in what happening?

A

two new origins migrate towards opposite poles while replication continues for rest of chromosome

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11
Q

7.2 b Replicated chromosomes are distributed actively to the daughter cells in binary fission

o Division of cytoplasm is accomplished by what?

A

Inward constriction of ring of cytoskeleton proteins

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12
Q

7.2 c Mitosis has evolved from an early form of binary fission

Is Prokaryotic mechanism of cell division effective? If so, why?

A

o b/c most prokaryotic organisms have single chromosome

 Means: daughter cell receiving minimum one copy of chromosome= genetic information = complete

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13
Q

7.2 c Mitosis has evolved from an early form of binary fission

Is Eukaryotic mechanism of cell division effective? Why or why not?

A

o b/c genetic info = divided amongst linear chromosomes, each chromosome has much greater length of DNA
o Daughter cell fails to receive a copy of chromosomes = lethal
o Most of cell cycle eukaryotic chromosomes = contained within nuclear membrane

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14
Q

7.2 c Mitosis has evolved from an early form of binary fission

o Bacteria + archaea have (an or no?) internal membrane around nucleoid

What does this mean for the organisms?

A

require different cellular and chromosomal machinery for distributing chromosomes to daughter cells (mitosis)

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15
Q

7.2 c Mitosis has evolved from an early form of binary fission
What is the evolutionary advancement of binary fission?

How does this benefit the cell?

A

• Evolutionary advancement: ability to hold two newly created molecules of double-stranded DNA (chromatids) following DNA synthesis

o Enables cells to keep track of chromosomes and orient them relative to cytoskeleton and ensure distribution to daughter cells

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16
Q

7.2 c Mitosis has evolved from an early form of binary fission

• Main components of cytoskeleton (are/aren’t?) present in ancestral prokaryotic cells, there (is/isn’t?) evolution

A

are, is

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17
Q

7.2 c Mitosis has evolved from an early form of binary fission

in higher eukaryotes what happens to the nuclear membrane at time when chromosomes are distributed

A

it disintegrates and reforms around daughter cells

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18
Q

7.2 c Mitosis has evolved from an early form of binary fission
What does variation in miotic apparatus result in?

What is a miotic apparatus?

A

evolution

a temporary structure in a dividing cell that enables the chromosomes to move to the poles of the cell

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19
Q
  1. 3 Mitosis and the eukaryotic cell cycle

- Eukaryotes require what to be genetic copies of parent

A

daughter cells

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20
Q
  1. 3 Mitosis and the eukaryotic cell cycle

- What are the 3 interrelated systems to eukaryotic mitosis?

A

o 1. Master program = orderly + timely progression through cell cycle
o 2. Process of DNA synthesis replicates each DNA chromosome into near perfect copies
o 3. Structural + mechanical web of interwoven cables + motors of cytoskeleton separates daughter cells

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21
Q
  1. 3 a Chromosmes are genetic units divided by mitosis

- The hereditary information of eukaryote chromosomes is distributed where? What does this enable?

A

= distributed among DNA molecules

= o DNA combines with proteins for stability
o Assist in packaging during cell division + expression of genes

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22
Q

7.3 a Chromosmes are genetic units divided by mitosis

Differnce between haploid, diploid, and ploidy?

A

Haploid:

  • Haploid= n chromosomes not in pairs (singular)
    o Yeast can be both haploid and diploid
    Haploid organisms/cells have only one set of chromosomes, abbreviated as n.

Diploid:
- 2 copies of each chromosome 2n

Ploidy:
- # of chromosome sets = ploidy

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23
Q
  1. 3 a Chromosmes are genetic units divided by mitosis

- Waht occurs Before cell divides in mitosis?

A

replication of DNA provides in given chromosomes produces 2 identical copies of DNA = chromatids

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24
Q
  1. 3 a Chromosomes are genetic units divided by mitosis
    - Eukaryotes contain copies of each chromosome in where?

Are humans haploid of diploid?

A

nucleus

diploid

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25
Q
  1. 3 a Chromosmes are genetic units divided by mitosis

- What are chromatids?

A

= held together by proteins called cohesins

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26
Q

7.3 a Chromosomes are genetic units divided by mitosis
o During mitosis what happens to the sister chromatids?
o Each daughter nucleus receives what from parent?

A

= separated

= same genetic info as parent

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27
Q

7.3 a Chromosomes are genetic units divided by mitosis

What is chromosome segregation?

A

 Equal division from cell division into daughter cells =

28
Q

7.3 a Chromosomes are genetic units divided by mitosis
 Precision + replication + segregation in cell cycle creates what?

 Mutations during replication create what?

A

= group of cells known as clones

= cells of clone genetically similar but not identical

29
Q

7.3 a Chromosomes are genetic units divided by mitosis

 Single cell (zygote) is what?

A

parent cell

30
Q
  1. 3 b Interface extends from one end of mitosis to the beginning of nest mitosis
    - Information of new daughter cell marks the beginning of what?
    - What is the first and longest stage
A

= (beginning of mitotic cell cycle)

= interphase

31
Q

7.3 b Interface extends from one end of mitosis to the beginning of nest mitosis

Interphase compromises of 3 phases of cell cycle, what are they?

A

 1 G1 phase
• Cell carries out function and grows
• Only phase of cell cycle that varies in length (others are uniform)
• Pace of division depends on G1
• Stage where cell types stop dividing (shunt from G1 known as G0 phase)
 2 S phase
• DNA replication and chromosome duplication
 G2 phase
• Brief gap in cell cycle where cell growth continues, and cell prepares for mitosis and cytokinesis

32
Q
  1. 3 b Interface extends from one end of mitosis to the beginning of nest mitosis
    - During all stages of interphase what happens to chromosomes?
A

= are organized and loosely packaged within nucleus

33
Q
  1. 3 b Interface extends from one end of mitosis to the beginning of nest mitosis
    - Internal regularory controls what?

o Internal controls are vulnerable to what?

A

= each phase of cell cycle (successful completion before next) also regulates # of cycles

= cells, viruses, and signal molecules (hormone)

34
Q
  1. 3 b Interface extends from one end of mitosis to the beginning of nest mitosis
    - In interphase the appropriate suite of genes are expressed for what?

What happens to DNA during interphase?

A

= cell maintenance and metabolism

= DNA is replicated

35
Q

7.3c After interphase, mitosis proceeds in 5 stages

Mitosis involves what sort of events? What happens during these events?

A

= Mitosis involves nuclear + cytoplasmic events

Nuclear:
In nucleus: normal gene expression decreases, DNA condenses and kinetochores = built up

Cytoplasmic:

  • In cytoplasm = cytoskeleton prepares for partitioning of chromosomes
36
Q
  1. 3c After interphase, mitosis proceeds in 5 stages

1. Prophase (before)?

A

a. Extended chromosomes replicated in interphase = condensed
b. Condensation packs long DNA molecules for division in mitosis
c. DNA compacted by winding double helix around small + charged protein to form nucleosome
d. Proteins = histones make up nuclear core
e. Short segment of DNA extends between one nucleosome and the next = linker
f. Solenoid = coiled structure of nucleosomes
g. During condensation = nucleus becomes smaller and disappears (shut down of RNA synthesis)
h. In cytoplasm, miotic spindle forms between two centrosomes during their migration to poles
i. Spindle = bundle of microtubules

37
Q
  1. 3c After interphase, mitosis proceeds in 5 stages

2. Prometaphase (in-between)

A

a. End of prophase, nuclear envelope breaks down
b. Bundles of spindles of microtubules, grow from centrosomes @ opposing poles towards centre
i. Attach @ Centro mirror of chromosomes
c. Two sister chromatins held together by cohesin proteins
d. Complex of proteins (kinetochore) has formed on each chromatid @ Centro mirror
e. Microtubules bind to kinetochores = connection determine outcomes of mitosis b/c they attach sister chromatids of each chromosome to microtubules leading to opposite poles one big web
i. Microtubules that don’t attach to chores, overall, those from opposite poles

38
Q
  1. 3c After interphase, mitosis proceeds in 5 stages

3. Metaphase

A

a. Spindle reaches final form; chromosomes move onto spindle alignment = metaphase plate
b. Chromosomes complete condensation, X shape (based on location of centromirror and length and thickness of chromatin arms)
c. When arms are assembled @ midpoint with two sister chromatids, metaphase leads to actual separation of chromatids
d. Only chromosomes with Centro mirror towards mirror have X shape
e. Chromosomes take on visible shape only when highly condensed
f. Karyotype = fully arranged condensed chromosomes
i. Very distinctive

39
Q
  1. 3c After interphase, mitosis proceeds in 5 stages

4. Anaphase (back) (segregation of whores to opposing poles brothel style)

A

a. Sister chromatids separate and move to opposing spindle poles
b. Kinetochores move towards opposite poles = first sign of movement
c. Movement continues until chromatids (known as daughter chromosomes) reach two poles = segregation

40
Q
  1. 3c After interphase, mitosis proceeds in 5 stages

5. Telophase (end) (pimp phase)

A

a. Spindle disassembles and chromosomes at each pole de-condense + return to extended state of interphase
b. Condensation proceeds= reapportion of nucleolus
c. RNA transcription resume + reformation of nuclear envelope around chromosomes @ each pole = two daughter nuclei
d. Cytoskeleton resumes normal responsibilities (not managing whores)
e. nuclear division is complete, cell has two nuclei
- chromosomes = composed of pair of nucleic acid backbones making up DNA double helix
- DNA molecules may attach to each other as sister chromatids
- B/C sister chromatids remain attached to each other following DNA synthesis, referred to as one chromosome
- Before replication, one chromosome is composed of one DNA double helix, after composed of two double helixes
o DNA replication increases amount of DNA in nucleus but not number of chromosomes
o During cell division, each of daughter cells receives one of sister chromatids

41
Q
  1. 3 d cytokinesis completes cell division by dividing cell division of daughter cell
    - What is Cytokinesis? What does it follow? What does it produce? During what phases does it occur?
A

= division of cytoplasm

= o Follows nuclear division stage of mitosis, produces two daughter cells containing one of daughter nuclei
o Begins during telophase or anaphase

42
Q

7.3 d cytokinesis completes cell division by dividing cell division of daughter cell

o Completion of cytokinesis means what?
- Does this occur via same or different pathways?

A

= (2 new cells that have progressed to interphase)

= o Proceeds by different pathways

43
Q

7.3 d cytokinesis completes cell division by dividing cell division of daughter cell

Animals + Fungi vs Plants in cytoplasmic division?

What determines cytoplasmic division?

A

 Animals and fungi: cytoplasm cut into two parts
 Plants: new cell wall (cell plate) forms between daughter nuclei and grows until it divides cytoplasm

= o Cytoplasmic division: determined by layer of microtubules @ formal spindle mid-point

=  Furrowing: layer of microtubules @ formal spindle midpoint expands laterally until stretches between dividing cells

44
Q

7.3 d cytokinesis completes cell division by dividing cell division of daughter cell

During furrowing, what does the developing layer consist of + what does this create?

How is furrowing powered? Results in what?

A

= • Developing layer = band of microfilament inside plasma membrane develops = creates belt in between layers

= • Powered by motor proteins = microfilament is constricted to help cell divide (belt tightens for division)
• Constriction = groove in plasma membrane (furrow) resulting in separation of daughter cells

45
Q

7.3 d cytokinesis completes cell division by dividing cell division of daughter cell

• What is cytoplasmic division? Function?

A

= isolation of daughter nuclei in daughter cells + distributes organelles and other structures equally between daughter cells

46
Q

7.3 d cytokinesis completes cell division by dividing cell division of daughter cell

o What is Cell plate formation?

• Vesicles contain components of what?

A

=  Plant cells are walled: plane of cell division = important
 Plate cell formation, layer of microtubules @ spindle mid point = organixing site by vesicles produced by ER and golgi complex

= cell wall

47
Q

7.3 d cytokinesis completes cell division by dividing cell division of daughter cell

 the fusion of vesicle walls results in what forming?

A

= formation of cell plate (stretching across former spindle mid point)

48
Q

7.3 d cytokinesis completes cell division by dividing cell division of daughter cell

Vesicle membrane fuses with what to create what?

A

fuses with plate to form cell wall

49
Q

7.4 Formation and Action of the mitotic spindle

What is the Mitotic spindle central to?

Made up of?

What does mitotic activity depend on?

A

= central to mitosis and cytokinesis

= Made up of microtubules and proteins

=  Activity depends on changing patterns of organization during cell cycle

50
Q

7.4 Formation and Action of the mitotic spindle

Microtubules are a major part of what phase?

When mitosis approaches what do the microtubules do?

A

= interphase cytoskeleton of euk. Cells

= Mitosis approaches = microtubules disassemble from interphase arrangements and reorganize into spindle (which grows until fills near entire cell)

51
Q

7.4 Formation and Action of the mitotic spindle

• Reorganization of microtubules follows one of 2 paths. Describe.

A

follows one of 2 paths (depends on presence/absence of centrosome in interphase)
o One organized spindle formation = same with or w/o presence of centrosome

52
Q

7.4 a Animals and Plants form spindles in different ways

Do Animal and protists have chromosomes? What extends from this cite? Describe this site.

A

o Have centrosomes: site near nucleus where microtubules go outward in all directions
 Main microtubule organizing centre of cell, anchoring microtubule cytoskeleton during interphase and positioning cytoplasmic organelles
 Contains pair of centrioles
• Important to mitotic spindle
• Function: generate microtubules needed for flagella/cilia (aka cell motility)

53
Q

7.4 a Animals and Plants form spindles in different ways

  • DNA replication in S phase?
  • Prophase in M phase?
  • Late prophase:
A

= centrioles in chromosome duplicate producing 2 pairs of centrioles

= : centrosomes separate into 2 parts
o Duplicated chromosomes (with centrioles inside continue to separate until they reach opposite poles)
o Movement of centrosomes = microtubules between lengthen and increase

= centrosomes = fully separated,
o microtubules extend between = large mass – early spindle
o when nucelar envelope breaks down @ end of prophase = spindle moves into region once occupied by nucleus and grows until it fits cytoplasm
o microtubules grow in length
o Asters = centrosomes at the spindle tip (from pole ends)
 Separation = spindles ensure daughter cells receive pair of chromosomes
• No centrioles or centrosome present in flowering plants

54
Q

7.4 a Animals and Plants form spindles in different way

Asters?

A

= centrosomes at the spindle tip (from pole ends)

55
Q

7.4 b Mitotic Spindles can move chromosomes by a combination of two mechanisms

  • Fully formed spindles @ metaphase = contain what?
    o 1. Kinetochore microtubules?

 Chromosome move toward poles via what?

o 2. non-kinetochore microtubules?

The Separation of chromosomes @ anaphase are a combo of what 2 groups?

A

= many microtubules (2 groups)

=  Connect chromosomes to spindle poles
 Chromosomes climb to poles via microtubules using motor proteins in kinetochores
 Tubulin subunits of kinetochore microtubules disassemble when kinetochore climbs (microtubules shorten as a result)
 Kinetochore microtubules do not move with respect to poles during anaphase

= motor proteins @ spindle poles pull kinetochore microtubules poleward (disassembly of microtubules into tubulin)

=  Extend between spindle poles w/o connecting to chromosomes (form microtubule overlap)
 Elongation of spindles = cell elongation in metaphase and anaphase
 Pushing movement = produced by microtubules sliding over one another (overlap) powered by microtubule motors (ex of dynein movement)

= kineto and non-kinetochores

56
Q
  1. 5 b Cell-Cycle checkpoints ensure accurate cell division
    - Cell has control points aka what?
  • 3 key checkpoints
    What do they do?

Describe each?

A

= control proteins = cyclins

= (prevent next phase from occurring until current phase is carried out effectively)

  1. G/S1 Checkpoint:
    a. Main point in cell cycle
    b. Cell cycle arrest = cell stops proceeding through cell cycle if DNA is damaged
    c. Primary checkpoint for extracellular reading for cell growth and division (hormone or growth factor absent = potential arrest)
  2. G2/M checkpoint
    a. Junction b/w G2 and M phases
    b. Arrests occur if = DNA not replicated fully in S, DNA is damaged
  3. Mitotic spindle checkpoint
    a. Within M phase before metaphase
    b. Assesses whether chromosomes are attached properly to mitotic spindle for proper metaphase plate alignment
    c. Essential for production of daughter cells
    d. One cell begins anaphase = irreversibly committed to completing M
57
Q
  1. 5 c Cyclins and cyclin-dependant kinases are the internal controls that directly regulate cell division
    - Regulation of cell = internal control system of protein cyclins and enzymes called

 Activity of CDK =

 Concentration of cyclins change in cell cycle (b/c of what?

 Regulation of cyclin-CDK complexes activity are coupled with what ?

A

= cyclin-dependant kinases
o CDK = protein kinase that phosphorylates + regulates activity of target proteins

= DNA replication, mitosis, cytokinesis
 Cyclin dependant b/c their activity depends on if they are bound to cyclin molecule

= synthesis and degradation), concentration of CDK = constant

= cell-cycle checkpoints

58
Q
  1. 5 d External controls coordinate the mitotic cell cycle of individual cells with the overall activities of the organism
    - Internal controls regulating cell-cycle = respond to what?

o Animals signal molecules?
o Plant signal molecules?

  • External factors bind to what? what does this trigger?

o Effects what?

o Cell surface receptors in animals = recognize contact with molecules of extracellular matrix – results in what?

A

= signal molecules (from outside of dividing cell)

= peptide hormones, and growth or death factors

= growth hormones

= bind to receptors on cell surface, response = triggering of reactions inside of cell (often include adding phosphate to cyclin-CDK complexes – affects function)

= speed, slow, stop progress of cell division

= in inhibit division of cell (contact inhibition)

59
Q
  1. 5 e Stem cells exhibit asymmetric cell division

- What is Asymmetric cell division

A

= producing twin daughter cells

60
Q

7.5 f Most cells in multicellular body cannot divide indefinitely

  • what is Cellular senescence?
  • What are the 2 contributing factors?
A

= loss of constant division ability over time

= 1. DNA damage

  1. Telomere shortening
    a. Telomere: repetitive DNA sequences added to end of chromosomes
    b. Once telomere diminish to minimum length = cell division stops
61
Q
  1. 5 g Cell-cycle controls are lost in cancer

- What are Cancer cells? What do they do to the CDK cyclin-system?

A

= mutations in variety of genes, many encode cyclin-CDK system- when mutated = oncogenes
o System breaks down = no more checkpoints, unlimited division

62
Q

7.5h Some cells are programmed to die

  • What is Apoptosis
    o Initiation of cell death results from what?
    o Can healthy cells undergo apoptosis? Why?
A

= programmed cell death
o Ancient mechanism common in mult. Euk.

= internal or external signals

= for specific functions (fingers result of web skin cell apoptosis)

63
Q

8.1 Mechanism of Genetic Recombination

  • Genetic variability in population allows populations to what?
    o What is the source of variability in populations?:
    o Diversity is amplified by what? What is this process called?
A

= evolve

= mutation in DNA sequence

= = amplified via shuffling of existing mutations in different combos: Genetic recombination
 Genetic recombination = origin of sexual aspect
 Without genetic recombination = asexual reproduction (clones)

64
Q
  1. 1 Mechanism of Genetic Recombination
    - Recombination requires what?

What is DNA?

DNA Recombination occurs between what regions?

What does Homology allow?

A

= o 2 DNA double helix
o Mechanism for bringing DNA into proximity + collection of enzymes for “cut, exchange, paste” DNA

= - DNA:
o Double helix
o Sugar phosphate backbones (winds)
 Held together by strong covalent bonds
o Paired bases (ribs)
 Pairs with partners via weak hydrogen bonds
• H bonds can be broken = separates DNA molecule = forms template for cell division replication

= regions of similar DNA base sequences
o Regions = homologous

= allows diff. DNA molecules to position and combine
o Homologous regions of DNA:
o Paired with enzymes that separate H bonds of one double helix + allows reassociation of bases with complimentary bases homologous (non-sister) chromatid
 Involves cutting sugar-phosphate group and linking to non-sister chromatids

65
Q

8.1 Mechanism of Genetic Recombination

What is one recombination event?

A

Cutting and pasting 4 DNA backbones

66
Q

What is Sexual Reproduction?

What is an Evolutionary advantage to sexual reproduction?

A

= Produces offspring by male/female union (gametes)
o Meiosis produces gametes with half chromosome number

= : genetic shuffling of sex = unique offspring

Biology 101 (17 decks)

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