Test 7 - Lecture 6

Question 1

How is the gene structure different for prokaryotic and eukaryotic DNA (and in general pre-mRNA created during transcription)?

Answer 1

Eukaryotes contain introns and have RNA splicing

Question 2

In eukaryotic organisms, the genes are interrupted by sequences that are not represented in the mRNA protein (not everything is a blueprint within the DNA). The non-coding DNA that interrupts the sequence of the genes is called the ___ and ___ are the coding sequences. Fill in the blanks

Answer 2

Introns, exons

Question 3

Eukaryotic organisms complete RNA splicing in between the translation and transcription phases of gene expression. What is RNA splicing?

Answer 3

A process that removes introns and per-mRNA and brings exons together to start translation

Question 4

Eukaryotic organisms complete RNA splicing in between the translation and transcription phases of gene expression. Where does RNA splicing occur within a cell?

Answer 4

Nucelus

Question 5

Eukaryotic organisms complete RNA splicing in between the translation and transcription phases of gene expression. What is the function of snRNPs involved in this process?

Answer 5

Responsible for the removal of introns

Question 6

Eukaryotic organisms complete RNA splicing in between the translation and transcription phases of gene expression and near the end of the process, a spliceosome begins to form. What is a spliceosome?

Answer 6

Catalyst that assists in the removal of introns

Question 7

Eukaryotic organisms complete RNA splicing in between the translation and transcription phases of gene expression. Which statement does not describe the steps of this process of RNA splicing? (Listed are true statements)

Answer 7

1. Pre-mRNA cuts at 5’ end and joins to the branch point inside the intron, which creates the lariat-shaped molecule
2. The 3’ end is cut and the two exons are joined together, causing the intron to be released and removed

Question 8

Regarding eukaryotic genes, what is the rule for the number and size of the introns and exons per gene?

Answer 8

There are no rules regarding the number or size of introns and exons per gene

Question 9

Regarding eukaryotic genes, why does RNA splicing occur in the first place?

Answer 9

There is no one theory to why it occurs, except for exon shuffling which is the theory that exons represent functional domains of proteins and that the intron-exon arrangement found in genes represent the shuffling of these functional units over a long period of time

Question 10

Regarding eukaryotic genes, what is alternative splicing?

Answer 10

Single primary transcript can be spliced into different mRNAs by the inclusion of different sets of exons

Question 11

Know what is occurring during each step of this overview of transcription and translation if this question is chosen. (look at the picture on chapter fifteen slide thirty-one)

Answer 11

N/A, See Picture

Question 12

Which statement does not describes a difference between prokaryotic and eukaryotic gene expression? (Listed are true statements)

Answer 12

mRNA Molecules: Prokaryotic will often contain transcripts of several on them, Eukaryotic will rarely have transcripts of more than one gene

mRNA Transport: Eukaryotes will have to be protected to leave the nucleus from cytoplasm to ribosome, Prokaryotes have translation and transcription done at the same time and will not have to be transported anywhere

Translation Beginning: Prokaryotic transcription and translation at the same time for prokaryotes, Eukaryotic does one at the time, In common: AUG

Question 13

Genes can be altered by random mutations or external factors. Which statement accurately describes (a) a base substitution or (b) chemical modification?

Answer 13

A) Spontaneous pairing errors during DNA replication
B) A base may be chemically altered by a mutagenic chemical

Question 14

Genes can be altered by random mutations or external factors. Which statement accurately describes (a) DNA breaks, (b) frameshift mutations, or (c) triplet expansion?

Answer 14

A) Ionizing radiation can cause sound-strand breaks in DNA loss of short segments
B) Also called slipped mispairing, short deletion near the start, ends, or middle of a codon (genes read incorrectly)
C) Adds additional copies of repeated 3-base sentences

Question 15

Why is it that some genes cannot be transcribed? (we discussed the answer on the very last slide of chapter fifteen)

Answer 15

Some genes cannot be transcribed if they are adjacent to a tightly coiled region of a chromosome

Question 16

Mutations can arise from changes in gene positions. Which statement accurately describe (a) translocation, (b) inversions, or (c) duplication errors?

Answer 16

A) Segment of a chromosome becomes part of another chromosome
B) The orientations of a portion of a chromosome is reversed
C) Doubling

Question 17

Mutations can arise from changes in gene positions. Which statement accurately describe (a) insertions or (b) deletions?

Answer 17

A) Inserting a whole bunch of info there wasn’t there prior
B) Deleting entire segments of a chromosome

Question 18

Regarding chromosomes, what is the difference between aneuploidy and polyploidy?

Answer 18

Aneuploidy: Whole chromosomes are lost or gained
Polyploidy: When you can add entire sets of chromosomes