Question 1

Noncoding DNA

Accepted Answer

- most eukaryotic genomes contain large amounts of noncoding - differences in sizes of eukaryotic genomes are reflected by amounts of noncoding DNA - play roles in regulation of gene expression - allow genes to be expressed in alternate ways

Question 2

Exons

Accepted Answer

coding sequences in genes

Question 3

Introns

Accepted Answer

- noncoding sequences in genes - make up more that 90% of avg. human gene - present in most complex eukaryotes - not found in most simple eukaryotes ( like yeasts) - rare presence in prokaryotes.

Question 4

Describe the mRNA relation to introns and exons

Accepted Answer

entire gene is transcribed to RNA but introns are removed by splicing, so that only exons are included in mRNA

Question 5

Histone genes

Accepted Answer

lack introns

Question 6

Alternative splicing

Accepted Answer

introns allow exons of a gene to be joined in different combinations, results in different proteins from the same gene

Question 7

Repetitive DNA sequences

Accepted Answer

- complex eukaryotic genomes contain highly repeated noncoding DNA sequences - can be present in hundreds of thousands of copies

Question 8

simple sequence repeats

Accepted Answer

-consists of tandem arrays of up to thousands of copies of short sequences, ranging from 1 to 500 nucleotides

Question 9

How can simple sequence repeats be separated?

Accepted Answer

- by equilibrium centrifugation in CsCl density gradients - AT rich sequences are less dense than GC rich sequences. - These repeat sequence DNAs band as satellites

Question 10

Satellite DNAs

Accepted Answer

repeat sequence DNAs seperate from the main band of DNA (in simple sequence repeats) - not transcribed - some play important roles in chromosome structure

Question 11

What can multiple copies of eukaryotic genes be used for

Accepted Answer

-to produce RNAs or proteins in large quantities, like ribosomal RNAs or histones

Question 12

gene family

Accepted Answer

- a group of related genes - members may be transcribed in different tissue or at different stages of development

Question 13

Encoding of alpha and beta subunits of hemoglobin

Accepted Answer

encoded by gene families; different members of these families are expressed in embryonic, fetal, and adult tissues

Question 14

Theory of gene family rise

Accepted Answer

-duplication of an original ancestral gene, followed by mutation and divergence of different family members.

Question 15

What is the result of gene family presence?

Accepted Answer

- proteins optimized for different functions - some mutations result in loss of function

Brainscape's Knowledge GenomeTM

(1) Chapter 6: Genes and Genomes Flashcards

Brainscape's Knowledge Genome^TM