Chapter 10: DNA To RNA To Proteins

Question 1

What is Gene Regulation?

Answer 1

THE PROCESS IN WHICH CERTAIN GENES ARE TURNED ON AND OFF.
Control the timing, location, and amount in which genes are expressed!

Question 2

What is Gene Expression?

Answer 2

WHEN A GENE IS TURNED ON AND TRANSCRIBED INTO mRNA

Information will flow from genes to proteins.

Question 3

What is a Gene?

Answer 3

Basic and functional unit made of DNA.
Genes act as instructions to be transcribed into RNA and ultimately result in the creation of functional products like proteins.

Question 4

When can genes be expressed?

Answer 4

GENES CAN BE EXPRESSED ONLY when the DNA double helix is visible.

Question 5

What is a codon?

Answer 5

A triplet of bases, which codes for ONE amino acid.
RNA and DNA are read in three.

Question 6

What is the star codon/amino acid?

Answer 6

AUG (codon)
MET (amino acid)

Question 7

The genetic code is…

Answer 7

REDUNDANT
-With more than one codon for some amino acids.
UNAMBIGOUS
-One code for one amino acid does NOT code for any other amino acid.
NEARLY UNIVERSAL
-Genetic code is shared by organisms
WITHOUT PUNCTUATION
-Codons are adjacent to each other with no gaps in between.

Question 8

What is Transcription? Where does it occur?

Answer 8

The transfer of genetic material from DNA into RNA molecules and occurs in the nucleus.

Question 9

What is translation? Where does it occur?

Answer 9

The transfer of information from RNA to proteins and occurs in the cytoplasm.

Question 10

What are the different types of RNA?

Answer 10

Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)

Question 11

What are the nitrogenous bases in RNA? The sugar base?

Answer 11

Cytosine (C)
Guanine (G)
Uracil (U)
Adenine (A)
Sugar base is Ribose

Question 12

What are the nitrogenous bases in DNA? The sugar base?

Answer 12

Cytosine (C)
Guanine (G)
Thymine (T)
Adenine (A)
Sugar base is DEOXYribose.

Question 13

RNA Polymerase

Answer 13

An enzyme that adds the RNA nucleotides by adding uracil.

Question 14

What is the first step in Transcription?

Answer 14

Initiation
RNA polymerase is used.
PROMOTER (a nucleotide sequence) will signal the of “start transcription”

Question 15

What is the second step of transcription?

Answer 15

Elongating
It will make the strand long.
RNA nucleotides line up along one strand of the DNA following the base pairing rules.

Question 16

What is the third step of transcription?

Answer 16

Termination
Uses a TERMINATOR
Releases a pre-mRNA strand
The single-stranded mRNA peels away and the DNA strands rejoin.

Question 17

Before leaving the nucleus what happens to pre-mRNA in eukaryotic cells?

Answer 17

The pre-mRNA is processed, and a cap and a tail are added to the ends.

Question 18

Introns

Answer 18

Noncoding segments that are spliced out.

(These coding segments do not code for proteins which is why they are removed)

Question 19

Exons

Answer 19

The coding sequence of DNA.This is the DNA that will be expressed.

Question 20

What occurs after transcription?

Answer 20

Translation.

Question 21

What does mRNA carry?

Answer 21

carries a transcript of the genetic code.

Question 22

What does tRNA carry?

Answer 22

Carries amino acids.
Matches amino acids with codons in mRNA using anticodons.

Question 23

Anticodons

Answer 23

Compliment codons.

Question 24

Ribosomes

Answer 24

Contain and made of ribosomal RNA (rRNA)
Coordinate the functions of mRNA and tRNA.
Made up of two subunits.

Question 25

Where is tRNA, mRNA and rRNA created?

Answer 25

In the nucleus.

Question 26

What do ribosomes build?

Answer 26

polypeptides.

Question 27

What is the first stage of translation and what occurs?

Answer 27

Initiation.
The initiating codon AUG (amino acid MET) marks the start of the mRNA message.
It will bring together mRNA and tRNA bearing the first amino acid.
The two subunits of a ribosome come together.

Question 28

What is the second stage of translation and what occurs?

Answer 28

Elongation.
Elongation will occur until the termination stage.
*tRNA carries an amino acid with it and will transfer it once it finds the complementary base on the mRNA.
* tRNA anticodons will lock into mRNA codons to create a chain of amino acids
*After tRNA binds to the ‘A’ site the tRNA in the ‘P’ site will transfer the chain of amino acids to site “A”
* To keep the polypeptides in the ribosome tRNA in site “A” will switch over to site ‘P’
*A new tRNA will lock in the large subunit site ‘A” and the process continues until the stop codon terminates the process.

Question 29

What is the third stage of translation?

Answer 29

Termination
A release factor attaches at the STOP codon and the entire ribosome complex comes apart releasing the completed polypeptide.

Question 30

What is a key major difference of gene expression in prokaryotic cells and eukaryotic cells?

Answer 30

Prokaryotic cells lack a nucleus so mRNA produced by transcription is immediately translated without additional processing.
as for the eukaryotic cells, the nucleus provides a
separate compartment for transcription.

Question 31

Cell Signaling

Answer 31

1. A signaling molecule is released and binds to a receptor protein on the plasma membrane of a cell.
2. The receptor is activated by the binding.
3. The signaling transduction pathway, will amplify the original signal.
4. Protein receptor travels into the nucleus binding to DNA.
5. Protein receptor binding to the DNA begins transcription.
6. Then releases mRNA to begin translation to create proteins.