cycle 8: Regulation of gene expression

Question 1

What is the site of transcription where DNA is transcribed into mRNA?

Answer 1

Nucleus

Also where transcription factors are synthesized.

Question 2

Where does translation occur in the cell?

Answer 2

Cytoplasm

Site where mRNA is translated into proteins.

Question 3

What is the function of the Rough Endoplasmic Reticulum?

Answer 3

Protein synthesis for proteins destined for secretion or membrane insertion.

Question 4

What organelle modifies, sorts, and packages proteins?

Answer 4

Golgi Apparatus.

Question 5

What is the site of ATP production in the cell?

Answer 5

Mitochondria.

Question 6

What is the role of lysosomes in the cell?

Answer 6

Degradation of cellular waste.

Question 7

What is the function of peroxisomes?

Answer 7

Breakdown of fatty acids and detoxification.

Question 8

Define Differential Gene Expression.

Answer 8

Different cell types express distinct genes due to tissue-specific transcription factors.

Question 9

What is Temporal Gene Expression?

Answer 9

Genes expressed at different stages of development or in response to stimuli.

Question 10

What does transcriptional regulation control?

Answer 10

Control at the promoter and enhancer level by transcription factors.

Question 11

What mechanisms are included in post-transcriptional regulation?

Answer 11

RNA splicing, RNA editing, and microRNA control.

Question 12

What is the focus of translational regulation?

Answer 12

Control over mRNA translation efficiency.

Question 13

What types of modifications are involved in post-translational regulation?

Answer 13

Protein modifications such as phosphorylation, ubiquitination, and glycosylation.

Question 14

What does LacZ encode?

Answer 14

β-galactosidase, which hydrolyzes lactose into glucose and galactose.

Question 15

What is the function of LacY?

Answer 15

Encodes permease, which facilitates lactose entry into the cell.

Question 16

What gene do liver cells express related to cholesterol metabolism?

Answer 16

ApoB-100.

Question 17

What proteins do lens cells express for lens transparency?

Answer 17

Crystallin proteins.

Question 18

What do tissue-specific transcription factors do?

Answer 18

Bind to promoters and enhancers of tissue-specific genes.

Question 19

Where are transcription factors synthesized?

Answer 19

Nucleus.

Question 20

Where are transcription factors translated?

Answer 20

Cytoplasm.

Question 21

What is the recognition sequence for the 3’ splice site?

Answer 21

NCAGG (N = any nucleotide).

Question 22

What is the mechanism of pre-mRNA splicing?

Answer 22

Recognition of 5’ and 3’ splice sites, formation of the spliceosome, removal of introns and joining of exons.

Question 23

What mutation can lead to β-thalassemia?

Answer 23

Mutation introduces a new 3’ splice site resulting in a premature stop codon.

Question 24

What does ApoB-48 result from?

Answer 24

RNA editing by APOBEC-1.

Question 25

What type of regulation does RNA editing represent?

Answer 25

Post-transcriptional.

Question 26

What can mutations in introns lead to in β-thalassemia?

Answer 26

Aberrant splicing and production of abnormal mRNA.

Question 27

What therapy uses CRISPR/Cas9 technology for β-thalassemia?

Answer 27

CTX001 Therapy.

Question 28

What is the role of telomerase in cancer cells?

Answer 28

Enables unlimited proliferation.

Question 29

What is the Hayflick Limit?

Answer 29

Finite number of divisions a cell can undergo due to telomere shortening.

Question 30

What defines a zygote?

Answer 30

Totipotent stem cell capable of forming all cell types.

Question 31

What are the stages of differentiation from a zygote?

Answer 31

Zygote → Blastocyst → Embryonic Stem Cells → Specialized Cell Types.

Question 32

Define totipotent stem cells.

Answer 32

Zygote, forms both embryonic and extraembryonic tissues.

Question 33

What type of stem cells are embryonic stem cells?

Answer 33

Pluripotent.

Question 34

What is the characteristic of multipotent stem cells?

Answer 34

Restricted to a family of related cell types.

Question 35

What are epidermal stem cells responsible for?

Answer 35

Regenerate skin by differentiating into keratinocytes.

Question 36

Where do intestinal stem cells reside?

Answer 36

At the base of crypts.

Question 37

What phase do stem cells remain in until activated?

Answer 37

G0 phase.

Question 38

What is the in vivo test for potency of stem cells?

Answer 38

Teratoma formation assay.

Question 39

What factors are used to reprogram somatic cells into iPSCs?

Answer 39

Oct4, Sox2, Nanog, Lin28.

Question 40

What are iPSCs used for in burn victims?

Answer 40

Create skin grafts with complete skin layers.

Question 41

What is pharmacogenetics in relation to iPSCs?

Answer 41

Model patient-specific drug responses for tailored therapy.