How Cells Work (Central Dogma) pt. 1b

Question 1

An ________ (in procaryotes) consists of a promoter, genes, and a terminator

Answer 1

operon

Question 2

Initiation begins with binding of _____ to _______ region of DNA.

Answer 2

sigma factor
promoter region

Question 3

____ vary in binding affinity for the sigma factor.

Answer 3

Promoters

Question 4

When the sigma factor is released, ____ begins

Answer 4

elongation

Question 5

m-RNA synthesis stops when RNA polymerase encounters a _____ (specific sequence of bases) (can vary in strength also).

Answer 5

terminator

Question 6

_____ can be polygenic (multiple genes controlled by one promoter).

Answer 6

Prokaryotic transcription

Question 7

______ do not do polygenic messages

Answer 7

Eukaryotic

Question 8

In procaryotes, _____ occur simultaneously because they don’t have nuclear membrane.

Answer 8

transcription and translation

Question 9

m-RNA in eukaryotes can have nonsense segments, called ______.
Opposite is _____

Answer 9

introns (non-coding, remove through splicing)
exon (coding)

Question 10

• m-RNA in eukaryotes undergo further _____.
• m-RNA ______.

Answer 10

processing
splicing

Question 11

_____ make it more difficult to transfer eucaryotic genes to procaryotes.

Answer 11

Introns

Question 12

Other mRNA processing steps:

• Do not occur in _____.
• ________ – 5’ end is modified by the addition of a guanine nucleotide with a methyl group attached.
• ____ – a string of adenine nucleotides is added to the 3’ end.

These processes are thought to increase m-RNA stability and facilitate transport across the _______.

Answer 12

prokaryotes
RNA capping
Polyadenylation
nuclear membrane

Question 13

Translation (making protein)

Three translation substeps

Answer 13

Initiation, elongation, and termination

Question 14

In prokaryotes, initiation is the formation of a _______ rRNA initiation complex

Answer 14

30s and 50s

Question 15

____ means ribosomal RNA, 30s and 50s are the sizes of two parts of the ribosome.

If they are joined, they are called ________

Aside from that, 3 proteins called _______, and the _______ energy from GTP should also be present.

Answer 15

r-RNA
70s ribosome

initiation factors
phosphate bond

Question 16

Translation: Making Proteins

In ____, m-RNA must first bind to the ribosomes

Answer 16

eukaryotes

Question 17

Translation: Making protein

All protein synthesis begins with the _____ initiation codon.

Answer 17

AUG

Question 18

_____ encodes for N-formyl methionine
(special amino acid)

Answer 18

Initial AUG

Question 19

_______ encodes regular methionine.

Answer 19

middle AUG

Question 20

________ ; ten nucleotides upstream the initial AUG.

Answer 20

Shine-Dalgarno box (AGGAGGU sequence)

Question 21

Elongation uses tRNA with attached amino acids as _______.

Answer 21

decoders

Question 22

“____” of tRNA match the codons on
mRNA

Answer 22

anti -codons

Question 23

Three letter “words” of four possible letters (_____) form “______” on mRNA (64 possible, many redundant).

Answer 23

UCAG
“codons”

Question 24

Process of Translation (making protein)

The _____ approaches the ribosome then the ribosome reads the _______.

Upon reading, the ribosome produces ________.

Once the 5’ enters the ribosome, the ______ helps to produce polypeptide.

Answer 24

mRNA
message
polypeptides
tRNA

Question 25

_____, _____ and _____ signals to **stop** ____ is the **initiation**

Answer 25

UAA, UAG, UGA, AUG

Question 26

Three codons (_____) do not code for amino acids and are **stop codons**. **Translation stops** or translation terminations sequence.

Answer 26

(UAA, UAG, and UGA)

Question 27

Translation start codon is _____.

Answer 27

AUG

Question 28

Two sites on the ribosome for the tRNA called

Answer 28

P and A

Question 29

the ribosome is moving to **balance** the elongating polypeptide chain

Answer 29

Rachet mechanism

Question 30

When a nonsense codon is reached, the protein is **released** from the ribosome with a _______.

Answer 30

release factor

Question 31

A _____ can be **read simultaneously** by 10 to 20 ribosomes at once.

Answer 31

single m-RNA

Question 32

Post-translational processing: * ______ from ribosome undergoes further processing before becoming *truly* useful. * Sometimes several proteins must associate to form _______ or ________.

Answer 32

Polypeptides enyzme or structural protein

Question 33

chaperones (proteins) that assist in ____

Answer 33

folding

Question 34

signal sequence = a **sequence of 20-25 amino acids** on the front of a protein that **directs protein** to be secreted out of the cell. The signal sequence is clipped off during ________

Answer 34

Secretion

Question 35

secretion through the **cytoplasmic membrane**.

Answer 35

Procaryotes

Question 36

___________: transport **vesicles – bud** around the proteins and transport to the membranes. It can be transport thru ______, ______, or by _____

Answer 36

Eukaryotes nuclear pores, across membranes, or by vesicles.