Lecture 17

Question 1

(meiosis) cell division in which one … germ cell produces four … daughter cells

Answer 1

diploid; haploid

Question 2

(meiosis) prophase I in an organism in which 2n = 4
dipolid cell has two … of each chromosome. nuclear envelope … and … develop. homologs pair up to form …, … takes place and … become visible

Answer 2

homologues; breaks down; spindles; tetrads; crossing over; spindles

Question 3

crossing over occurs between … of a … homologous pair. it can increase …

Answer 3

non-sister chromatids; synapsed; genetic variation

Question 4

(meiosis) metaphase I:

… line up at the … … are visible

Answer 4

tetrads; metaphase plate; spindles

Question 5

(meiosis) anaphase I: the attachments between the homologous chromosomes … and … pull the chromosomes towards the poles

Answer 5

breaks down; kinetochores

Question 6

(meiosis) telophase I and cytokinesis:

chromosomes reach the poles, the … breaks down and … reform. Cytokinesis produces … daughter cells

Answer 6

spindle; nuclear envelopes; two

Question 7

(meiosis) prophase II:

the nuclear envelope .. and the spindles …

Answer 7

breaks down; reform

Question 8

(meiosis) metaphase II:

… line up on the …

Answer 8

sister chromatids; metaphase plate

Question 9

(meiosis) anaphase II: the centromeres that bind the sister chromatids together are …, enabling each chromatid to …

Answer 9

broken down; move to opposite poles

Question 10

(meiosis) telophase II and cytokinesis:
… chromosomes reach the poles, the … breaks down and … reform. Cytokinesis produces .. daughter cells (..) from the original single cell (…)

Answer 10

unduplicated; spindle; nuclear envelopes; four haploid; n=2; 2n=4

Question 11

(mitosis vs. meiosis)

prophase: in mitosis, … are present, in meisos I, … is formed by .. of ..

Answer 11

duplicated chromosome; tetrad; synapsis; homologous chromosomes

Question 12

(mitosis vs. meiosis) metaphase-
mitosis: … positioned at the metaphase plate
meiosis I: … positioned at the plate

Answer 12

chromosomes; tetrades

Question 13

(mitosis vs. meiosis) 
anaphase/telophase: 
mitosis: ... separate during anaphase 
meiosis I: ... separate  
mitosis 2: ... separate

Answer 13

sister chromatids; homologues; sister chromatids

Question 14

… separate during meiosis.

Answer 14

alleles

Question 15

mitosis is a process required for … and … of the organism
meiosis is a process required for the … of an organism

Answer 15

growth; development; sexual reproduction

Question 16

inheritance of characteristics is achieved during the process of

Answer 16

reproduction

Question 17

two factors determine characters:

1. ….
2. … during …

Answer 17

heredity; modification; development

Question 18

the inherited preformed or predetermined genetic program provides information about what is possible, but regulation of genetic expression involves … It is the latter that is …

Answer 18

interpretation; epigenetic

Question 19

epigenetics is a … process that affects the … of genes

Answer 19

reversible; expression

Question 20

the epigenome is responsible for: 
... distinct ... in mammals 
... gene expression in genomic imprinting 
... inactivation
... silencing of transposons

Answer 20

200; cell types; mono-allelic; X chromosome; transcriptional

Question 21

epigenetic factors:
DNA …
.. modification (…, …)
non-coding .. molecules

Answer 21

methylation; histone; acetylation; methylation; RNA

Question 22

methylation of DNA and histones causes nucleosomes to … transcription factors cannot … and genes are not …

Answer 22

pack tightly together; bind the DNA; expressed

Question 23

histone acetylation results in … of nucleosomes. transcription factors can bind the DNA and genes are …

Answer 23

loose packing; expressed

Question 24

methylation = ... of genes 
acetylation = genes are ...

Answer 24

reduced expression; available to be expressed

Question 25

epigenetic changes to the chromatin may result from: ... ... .../... ... ... and may result in: ..., ... disease, ... disorders, ...

Answer 25

development; environmental chemicals; drugs/pharmaceuticals; aging; diet; cancer; autoimmune; mental; diabetes

Question 26

epigenetics plays a role in the ... of gene expression

Answer 26

control

Question 27

cancer cells have a ... level of methylation (... DNA) than healthy cells. Too little methylation causes: - activation of genes that ... - chromosome ...: highly active DNA is more likely to be ..., ... and ... - loss of ...

Answer 27

lower; more active; promote cell growth; instability; duplicated; deleted; moved to other locations; imprinting

Question 28

cancer cells can also have genes that have ... methyl (are ... active) than nomral. the types of genes that are turned down in cancer cells: - keep cell growth .. - repair ... - initiate ...

Answer 28

more; less; in check; damaged DNA; programmed cell death

Question 29

DNA methylation occurs in

Answer 29

CpG islands

Question 30

1. before replication, DNA is fully ... at ... dinucleotides 2. During replication, new DNA strands are synthesized without ... 3. after replication, each new DNA molecule will have ... on one strand but not the other: the DNA is ... 4. methyl groups attract ... enzymes, which add methyl groups to the ... strand 5. resulting in fully .. DNA

Answer 30

methylated; CpG; methyl groups; methylation; hemimethylated; methyltransferase; unmethylated; methylated

Question 31

histone modificates are ... to daughter cells. new histones are synthesized in ... during the cell cycle. the modifications on histones happen after ... have formed

Answer 31

not passed on; G1; nucleosomes

Question 32

the genome dynamically responds to the environment: ..., ..., ..., ... and other factors activate chemical switches that regulate gene expression

Answer 32

stress; diet; behavior; toxins

Question 33

the epigenome changes in response to ..., which come from ... the cell, from ..., or from the ...

Answer 33

signals; inside; neighboring cells; outside world

Question 34

... can also directly affect the "epigenetic state" of DNA | ... from it are turned into ... groups

Answer 34

food; nutrients; methyl

Question 35

dificiency of methyl-donating folate or choline during late fetal or early postnatal development causes certain regions of the genome to be ... for life

Answer 35

under-methylated

Question 36

a mother's ... influences the epigenome of her offspring

Answer 36

diet

Question 37

... influences gene expression

Answer 37

dietary methyl