3.3 RNA Versus DNA

Question 1

Essential functions of RNA

Answer 1

• converts genetic code from DNA to proteins
• regulates the process of gene expression
• facilitates biological reactions
• senses and communicates responses to cellular signals
• exists as the genetic material found in some viruses

Question 2

5’ end

Answer 2

Beginning end of nucleic acid where phosphate group is found

Question 3

3’ end

Answer 3

Terminal end of a nucleic acid where a hydroxyl group is found

Question 4

Antisense strand

Answer 4

Strand of DNA that produces RNA

Question 5

Sense (coding) strand

Answer 5

Strand of DNA that will match with RNA, replacing U for T

Question 6

Time of mRNA degradation

Answer 6

After translation

Question 7

Structure of typical human protein coding mRNA

Answer 7

From 5’ to 3’

• cap
• 5’ UTR (untranslated region)
• start codon
• coding sequence
• stop codon
• 3’ UTR
• poly-a tail

Question 8

Polyadenylated tail

Answer 8

Poly-a tail

About 200 adenine residues added to mRNA at end of transcription to prevent the enzymes in the cytoplasm from degrading the mRNA

Question 9

tRNA

Answer 9

Gathers appropriate amino acids from the cytoplasm and delivers them to the ribosome.

Question 10

rRNA

Answer 10

Part of the ribosome mechanism that assembles the amino acids according to the mRNA sequence

Question 11

Frameshift mutations

Answer 11

Resulting from poorly defined start and stop locations during translations

Question 12

Tay-Sachs disease

Answer 12

Sometimes caused by frameshift mutations which lead to absence of hexosaminidase A enzyme. Causes a buildup of waste in nerve cells leading to nerve damage and eventually death.

Question 13

snRNA

Answer 13

Small nuclear RNA

Localized to the nucleus and involved in the splicing and processing of mRNA

Question 14

scRNA

Answer 14

Small cytoplasmic RNA

Present in the cytoplasm

Question 15

miRNA

Answer 15

Micro RNA

Small, highly conserved segments of non-coding RNA involved in. the regulation of gene expression

Question 16

siRNA

Answer 16

Regulates gene expression through RNA interference

Can be commercially synthesized

Question 17

RNAi

Answer 17

RNA interference
Silences genes by specifically targeting and degrading their mRNA

Question 18

Retrovirus

Answer 18

Has RNA as its genetic material. Uses reverse tanscriptase to covert RNA into DNA and integrates it into host DNA in order to replicate

Question 19

Four crucial steps for cells of a multicellular organism

Answer 19

1. Cell proliferation
2. Cell specialization and differentiation
3. Cell-cell interactions
4. Cell movement

Question 20

How long does a zygote stay single-celled?

Answer 20

12 hours

Question 21

How many cells are in a 3 day old zygote?

Answer 21

16 cells

Question 22

Amount of cells in an average human adult

Answer 22

About 3 trillion

Question 23

Proliferation

Answer 23

Create exact copies of a given cell

Question 24

Protein p53

Answer 24

Binds DNA to inhibit the development of and growth of tumors

• Can stimulate DNA repair
• stop cell w/ DNA damage from proceeding through cell cycle
• initiate apoptosis

Question 25

p53 mutation

Answer 25

Found in 50% of cancers
Can be inherited

Question 26

iPSC

Answer 26

Induced pluripotent stem cells

Reprogrammed adult cells that have been reprogrammed to be pluripotent

May have DNA abnormalities that develop from a lifetime of cell division

Question 27

Direct contact interactions

Answer 27

Connected cells with channels between them allow chemicals to diffuse between them

Question 28

Paracrine

Answer 28

Chemical signal diffuses out of one cell and reaches nearby cells

Question 29

Synaptic signaling

Answer 29

Specific type of paracrine signaling in the nervous system

Occurs between cells separated by a synapse

Neurotransmitters diffuse from one cell to another

Question 30

Autocrine signaling

Answer 30

Cell signals to itself by releasing chemicals that bind to receptors on the outside of the cell

Question 31

T-lymphocytes

Answer 31

Produce cytokine proteins that bind to the outside of the same cells to stimulate their own proliferation in order to initiate an immune repose

Question 32

Endocrine signaling

Answer 32

Signaling conducted by hormones that can travel throughout the body via the circulatory system