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exam3 Flashcards

chapter 10, 11, 12, 13: cell division 1 and 2, mendelian genetics, gene expression 1 - cell cycle, cell division, mitosis, sexual reproduction, chromosomal inheritance, dom and recessive traits, extensions of mendel

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Biology 101 flashcards
1
Q

describe the structure of prokaryotic and eukaryotic genomes

A
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2
Q

distinguish between chromosomes, genes, and traits

A
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3
Q

describe the mechanisms of chromosome compaction

A
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4
Q

genome def

A

a cell’s DNA, packaged as a double-stranded DNA molecule, is called its genome

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5
Q

eukaryotic v. prokaryotic genomes

A
  • prokaryotic cells have a genome with one double stranded DNA molecule
  • in eukaryotic cells the genome consists of several double-stranded DNA molecules
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6
Q

gametes v. somatic cells def + how many chromosomes they have in comparison

A

gametes = sperm or eggs
somatic cells = human body cells
- somatic cells have 46 chromosomes while gametes have 23 each

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7
Q

define diploid

A

a configuration of two matched or homologous sets of chromosomes (one set from each biological parent) in a typical body cell

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8
Q

define haploid

A

a configuration of one set of chromosomes; for e.g. gametes (or sex cells) in humans

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9
Q

define homologous chromosomes

A

a matched pairs of chromosomes in a diploid cell; upon fertilization where each gamete contributes one set of chromosomes
- same length

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10
Q

define genes + what they do

A

specific nucleotide segments within homologous chromosomes at the same location;
genes are the functional units of chromosomes, they determine specific characteristics by coding for specific proteins

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11
Q

define nucleotide segment

A

a nucleotide is an organic molecule that is the building block of DNA and RNA; making a nucleotide segment the sequence of A (adenine), T (thymine), G (guanine), C (cytosine) with the 5’ and 3’ ends
- or U (uracil) instead of T in RNA

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12
Q

what is the building block of nucleotides

A

phosphate group, sugar and nitrogenous base

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13
Q

define locus

A

a specific, fixed location on a chromosome where a particular gene or genetic marker is located

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14
Q

define genetic traits

A

the variations of genetic characteristics
e.g. characteristics = hair color
traits = blonde, brunette, black, ginger + all that’s in between

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15
Q

^^^from textbook notes

A

^^^from textbook notes

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16
Q

list some reasons why cells need to undergo cell division

A

tissue renewal, asexual reproduction, growth and development

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17
Q

what does each phase of the cell do; how long does each phase last

A

G0- resting state/post-mitotic state ~any

G1- first growth phase: assembling ingredients for DNA replication ~3-5 hours

S- DNA synthesis: DNA replication machinery at work ~10-12 hours

G2- second growth phase: double checking if S phase went okay, building up materials for cell division

Interphase- everything before mitosis (G1, S, G2)

M- mitotic phase: dividing genetic material (replicated chromosomes) into two daughter cells

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18
Q

explain each sub-phase during the cell cycle

A

(also explain interphase)

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19
Q

explain and draw DNA’s organization during diff stages of the cell cycle; how is DNA organized at different stages of the cell cycle

A
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20
Q

explain the relationship between chromosomes, genes, and DNA; what do the terms “DNA”, “chromosome”, and “gene” mean; similarities v. differences; how do they connect/interact with each other

A
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21
Q

how does DNA condense + when does DNA condense

A

DNA wraps around histones to form nucleosomes; the nucleosome coils into a chromatin fiber, which then further condenses around a scaffold that consists of several non-histone proteins until it forms a duplicated (eukaryotic) chromosome

DNA condenses into chromosomes before mitosis (specifically when _?)

22
Q

logic of mitosis

A

the chromosome is duplicated (DNA replication) into two sister chromatids, which are then separated into two cells each with their own sister chromatid

replicated chromosomes condense -> align -> separate

23
Q

anatomy of a chromosome

A

the two sister chromatids are held together by centromeres on each sister chromatid (anything else?)

24
Q

chromatins during interphase v. during mitosis

A

chromatins during interphase are loosely organized and resemble a plate of spaghetti; chromatins during mitosis are condensed and resemble gummy worms that are held together at one spot by two centromeres to form an ‘X’ (or ‘x’)

25
Q

define diploid

A

two copies of every chromosome

26
Q

what are chromosomes doing during the following phases and sub-phases: G2 of interphase, prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis

A

G2 of interphase- the chromosomes are loosely organized and resemble spaghetti
Prophase- chromosomes have condensed and duplicated into two sister chromatids for each chromosome
Prometaphase- have attached to kinetochore (smthing to do with the spindle…) and are starting to organize in the middle of the cell along the imaginary metaphase plate
Metaphase- organized along an imaginary plate/line in the middle of the cell
Anaphase- spindle microtubules are shrinking, causing the sister chromatids to be pulled apart/separated
Telophase and Cytokinesis- the cytoplasm is divided; the separated sister chromatids begin to de-condense inside the newly forming nuclear envelope

27
Q

what are centromeres and spindle microtubules doing during the following phases and sub-phases: G2 of interphase, prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis

A

G2 of interphase- centromeres have not formed and no microtubule spindle has formed, but is being organized; MTOC (microtubule organizing center)
Prophase- centromeres have formed and early mitotic spindle is reaching out
Prometaphase- overlapping microtubules attach to centromere region w/ the centrosomes the spindles stem from at opposite poles of the cell
Metaphase- centromeres remain at their respective spindle pole
Anaphase- spindle microtubules are shrinking back towards centrosome regions and separating the sister chromatids
Telophase and Cytokinesis- centrosomes remain in their own cell as the cytoplasm divides

28
Q

what is the nuclear envelope doing during the following phases and sub-phases: G2 of interphase, prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis

A

G2 of interphase- nuclear envelope is fully intact
Prophase- nuclear envelope is fragmenting/breaking down
Prometaphase- has completely gone away
Metaphase- still gone
Anaphase- still gone
Telophase and Cytokinesis- begins to form again in each of the two cells

29
Q

define spindle

A

microtubules that move chromosomes around during mitosis

30
Q

define microtubules

A

one component of the cytoskeleton and provide structural support + move chromosomes during mitosis

31
Q

centromere v. centrosome v. centriole

A

centromeres hold sister chromatids together in the central part of the chromosome and where microtubules attach during mitosis v. centrosome region MTOC- microtubule organizing center where microtubules grow from; cells usually have one centrosome region but duplicate during S phase v. centrioles are organelles that resemble bite-sized twizzlers and are where microtubules grow from, usually two per centrosome

32
Q

describe the role of the cytoskeleton (microtubules and actin microfilaments) in mitosis and cytokinesis

what is the actin microfilament (furrow?) doing during telophase and cytokinesis

A

the actin microfilaments form a contractile ring during telophase and cytokinesis that closes down and helps to separate the two cells

cytoskeleton??? microtubules???

33
Q

define homologous chromosomes

A
34
Q

what if a drug was made that prevents actin monomers from forming microfilaments

A

actin monomer is what makes up microfilaments, preventing this would result in _??? (cells having multiple nuclei??? what diff does it make??? why would you want that in a drug???)

35
Q

explain how the cell regulates transitions between stages during the cell cycle (using the terms ‘checkpoints’, ‘cyclins’, and ‘CDKs’)

A

checkpoints after each phase (G1, S, G2, M) on whether everything went smoothly/have the materials to continue
G1- materials for DNA replication? no damage to DNA? favorable environment?
S- errors?
G2- materials for mitosis?
M- spindle checkpoint, are microtubules firmly attached to kinetochore

cyclin dependent kinases add phosphate groups to substrates (target proteins) that once activated work on transitioning to the next phase in the cell cycle

36
Q

what are the materials needed for S phase?
what are the materials needed for M phase?

A

synthesis- nucleotides, organelles (such as?), enzymes (such as?)

mitosis- tubulin, cytoskeleton, proteins, replicated centrosomes

37
Q

define kinetochore

A

in the region of the centromere, where the spindle microtubules connect

38
Q

define cyclins and the purpose they serve

A

positive regulators of the cell cycle, they make sure the cell cycle is advancing smoothly; cyclin dependent kinases activate target proteins important for each stage of the cell cycle

cyclin binds to CDK (cyclin-dependent kinase), which has a phosphate donating protein that then activates a certain target protein (by attaching to it); protein goes on to advance the cell cycle (a bunch of parts playing telephone; unique cyclins for each phase of the cell cycle)

39
Q

contrast the roles of proto-oncogenes with those of tumor suppressors in the regulation of the cell cycle; when things go right v. when they go wrong; how do these two _ (genes?) tie into cancer

A

proto-oncogenes = accelerators for cell division
- correctly functioning = promote measured growth and proliferation of cells, and/or restrict cell death (called apoptosis)
- incorrectly functioning, “gain-of-function” (what does that mean) mutations lead to cancer via unregulated cell division

tumor suppressors = brakes for cell division
- functioning correctly suppress the proliferation by inducing cell cycle arrest (???), initiates DNA repair
- functioning incorrectly, “loss-of-function” mutations lead to cancer (also via unregulated cell division???)

40
Q

examples of proto-oncogenes and tumor suppressors

A

proto-oncogenes: cyclins + CDK’s, “happy signals” from neighboring cells
tumor suppressors: “unhappy signals” from neighboring cells

41
Q

define autosomes

A

any chromosome that is not a sex chromosome, i.e. 1-22 in humans

42
Q

define sister chromatids v. non-sister chromatids

A

two exact copies of each chromosome; present after DNA replication
v. same subset of genes but w/ slight differences (aka different alleles)

43
Q

define the following terms (IN PLACE TILL I GET BACK TO THIS PART/THESE TERMS)
- non-sister chromatids
- ploidy (diploid, haploid, etc)
- gene
- allele
- gametes
- germ cell
- synapsis
- chiasma (pl. chiasmata)
- recombination
- independent assortment
- chromosomal segregation
- non-disjunction
- aneuploidy

A
44
Q

mitosis v. meiosis

A

both are cell division processes; mitosis is one division and results in two daughter cells v. meiosis is two divisions and results in four daughter cells

mitosis- diploid (two chromosomes), identical genetic composition (happens all the time / every cell), one phase process*

meiosis- haploid (four chromosomes), different genetic composition (sexual reproduction / sex cells), two phase process*

*major difference

45
Q

logic of meiosis (using the key terms: gametes, and germ cell)

A

diploid (two pairs of sister chromatids / homologous chromosomes) germ cell (sex cell?) divides into two haploid daughter cells and then again divides into haploid gametes

46
Q

why is meiosis a two-phase process, what is the benefit

A

making cells with half as much genetic information (cells that are used for sexual reproduction)

fertilization: the two gametes will result in a diploid zygote with homologous chromosomes (the different parents’ genetic information is shared) ???

47
Q

define somatic cell

A

anything that is not a germ cell (skin cell, liver cell, etc)

48
Q

define synaptonemal complex

A

proteins that hold homologous chromosomes together

49
Q

explain the process of crossing over along with its benefits

A

crossing over is the process of exchanging alleles in prophase one; genetic diversity through

50
Q

explain the process of independent assortment along with its benefits

A

during metaphase one, the chromosomes separate into different arrangement of cells, and then again in metaphase two; this promotes more genetic diversity since the chromosomes can arrange themselves in numerous different ways

bio 111 (3 decks)

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