Test 3 Study Guide

Question 1

Alteration of chromatin structure

Answer 1

alterations in the way DNA is packaged within the nucleus of a cell; modifications through histone proteins and DNA methylation

Question 2

Site of binding of the DNA binding proteins

Answer 2

the major groove (recognize and interact with specific nucleotide sequences to perform functions like gene regulation); initiates important cellular processes like transcription, DNA replication, or DNA repair

Question 3

Negative repressible control of operons

Answer 3

gene expression is normally “on” but can be turned “off” by a repressor protein that binds to the operator region when a specific molecule, corepressor, is present

Question 4

Positive induction of operons

Answer 4

a regulatory protein/ an activator binds to DNA and enhances transcription of the operon genes only when an inducer is present

Question 5

Basal transcriptional apparatus for transcription

Answer 5

a set of proteins, including general transcription factors and RNA polymerase, essential for the basic initiation of transcription at a gene’s promoter region

Question 6

Stimulation of flowering in Arabidopsis

Answer 6

by exposure to long days (photoperiod), triggering the production of a protein, flowering locus (FT)

Question 7

DNase I sensitivity

Answer 7

regions of chromatin that are sensitive to cleavage by the DNase I enzyme

Question 8

Gene regulation by histones

Answer 8

regulates gene expression by compacting DNA and interacting with it through chemical modifications

Question 9

Different aspects of epigenetics

Answer 9

DNA methylation, histone modifications, noncoding RNA regulation, chromatin remodeling, epigenetic inheritance, role of environmental factors

Question 10

Sex determination in honey bees

Answer 10

fed “royal jelly”/ siRNAs (small inhibitor RNA) that suppress Dnmt3, less DNA methylation occurs, and expression of genes encoding queen characteristics; DNA methylation = worker bee, no/ less DNA methylation = queen bee

Question 11

Major event of retinoblastoma cancer

Answer 11

a change/ mutation in the RB1 gene; this gene helps prevent cells from growing out of control

Question 12

Colon cancer

Answer 12

ras mutations; 5-10% of colon cancer is hereditary

Question 13

Mutations in proto-oncogenes and tumor suppressor genes

Answer 13

mutations in proto-oncogenes transform them into oncogenes that promote uncontrolled cell division; mutations in tumor suppressor genes stop/ limit cell growth and can lead to them to lose inhibitory function

Question 14

Hardy-Weinberg equilibrium

Answer 14

large randomly breeding population, allelic frequencies will remain the same from generation to generation assuming there is no mutation, random mating, no gene flow, infinite population size and no selection

Question 15

How to figure out allele and genotype frequencies using Hardy-Weinberg equation

Answer 15

p^2 + 2pq + q^2 = 1; p is frequency of dominant allele, q is frequency of recessive allele, 2pq is frequency of heterozygous genotype

Question 16

Markers/ techniques used to investigate genetic variation

Answer 16

SNPs, SSR, RFLPs, AFLP, VNTRs;

single nucleotide polymorphisms (SNPs), micro-satellites (SSR), restriction fragment length polymorphisms (RFLPs), amplified fragment length polymorphism (AFLP), variable tandem repeats (VNTRs)

Question 17

Biological species concept

Answer 17

definition of a species as a group of organisms whose members are capable of interbreeding with one another but are reproductively isolated from the members of other species. Because different species do not exchange genes, each species evolves independently. Not all biologists adhere to this concept

Question 18

Genes and human disorders resulting from gene imprinting

Answer 18

Pader-Willi syndrome (low muscle tone in infancy, deletion of chromosome 15), Angelman syndrome (developmental delay, intellectual disability, etc; deletion of chromosome 15), Beckwith-Wiedemann syndrome (accelerated growth,, chromosome 11)

Question 19

CpG islands

Answer 19

in promotor regions; they are unmethylated near promoters of actively transcribed genes

Question 20

Structural gene

Answer 20

DNA sequence that encodes a protein that function in metabolisms or biosynthesis or that has a structural role in the cell

Question 21

Gene regulation

Answer 21

mechanisms and systems that control the expression of genes

Question 22

Repressible operons

Answer 22

operon in which transcription is normally on (taking place); something must happen to repress transcription/ turn it off

Question 23

Inducible operons

Answer 23

operon in which transcription is normally off (not taking place); something must happen to induce transcription/ turn it on

Question 24

Repressor

Answer 24

regulatory protein that binds to a DNA sequence and inhibits transcription

Question 25

Antisense RNA

Answer 25

small RNA molecule that base pairs with a complementary DNA or RNA sequence and affects its functioning

Question 26

Enhancer

Answer 26

sequence that stimulates maximal transcription of distant genes; affects only genes on the same DNA molecule (cis acting), contains short consensus sequences, is not fixed in relation to the transcription start site, can stimulate promoters in its vicinity, and may be upstream or downstream of the gene; the function is independent of sequence orientation

Question 27

Chromatin remodeling complexes (CRCs)

Answer 27

large, multi-protein assemblies that help cells access DNA by using ATP hydrolysis to alter, mobilize, and restructure the structure of nucleotides

Question 28

DNA methylation

Answer 28

modification of DNA by the addition of methyl groups by specific enzymes to certain positions on the bases

Question 29

Paramutation

Answer 29

when one allele creates a heritable alteration in another allele without change in DNA sequence

Question 30

Histone acetylase

Answer 30

histone tails are modified by the addition of an acetyl group; gene regulation; removes + charge on histones

Question 31

Polycomb group protein

Answer 31

a family of protein complexes that regulate chromatin and repress gene transcription in animals and plants; stem cell identity, differentiation and disease

Question 32

Gene imprinting

Answer 32

process that determines whether a gene is expressed based on whether it was inherited from the mother or father

Question 33

Clonal evolution

Answer 33

process by which mutations that enhance the ability of cells to proliferate predominate in a clone of cells, allowing the clone to become increasingly rapid in growth and increasingly aggressive in proliferation properties

Question 34

Metastasis

Answer 34

the movement of cells that separate from malignant tumors to other sites, where they establish secondary tumors

Question 35

Philadelphia chromosome

Answer 35

chromosome 9 and 22 break and exchange parts; genetic abnormality in leukemia cancer cells that occurs when part pf the ABL gene on chromosome 9 breaks off and attaches to the BCR gene on chromosome 22

Question 36

Gene pool

Answer 36

set of all genes in a population

Question 37

Inbreeding coefficient

Answer 37

a measure of inbreeding; the probability (ranging from 0 to 1) that two alleles are identical by descent

Question 38

Fixed allele frequency

Answer 38

a single allele at a specific gene locus is present in 100% of a population

Question 39

Ana and Cladogenesis

Answer 39

evolution taking place within a single lineage; evolution in which one lineage split into two

Question 40

Sympatric speciation

Answer 40

speciation that arises in the absence of any geographic barrier to gene flow, in which reproductive isolating mechanisms evolve within a single population

Question 41

Allopatric speciation

Answer 41

speciation that occurs when a geographic barrier splits a population into two groups and blocks the exchange of genes between them

Question 42

Phylogenetic tree

Answer 42

graphical representation of the evolutionary relationships among different organisms

Question 43

Cis regulatory elements

Answer 43

DNA sequences that control gene expression by binding to transcription factors and other DNA-binding proteins; regulate noncoding DNA sequences and regulate transcription of neighboring gene

Question 44

Trans regulatory elements

Answer 44

DNA sequences that regulate the expression of genes on different DNA molecules; encoding upstream regulators

Question 44

Horizontal gene transfer

Answer 44

transfer of genes from one organism to another by a mechanism other than reproduction

Question 45

Hardy-Weinberg Law

Answer 45

principle of population genetics stating that if a population is large; randomly mating; and not affected by mutation, migration, or natural selection, then allelic frequencies of a population do not change and the genotypic frequencies stabilize after one generation in the proportions p^2 (the frequency of AA, 2pq (frequency of Aa), and q^2 (frequency of aa), where p equals the frequency of allele A and q equals the frequency of allele a

Question 46

Constitutive gene

Answer 46

a gene that is not regulated and is expressed continually