Chapter 21

Question 1

genomics

Answer 1

the study of whole sets of genes and their interactions

Question 2

bioinformatics

Answer 2

the application of computational methods to store and analyze data

Question 3

Human Genome Project 1990

Answer 3

Aim- to determine the complete sequence of each chromosome

o This was all 3 billion pairs in a haploid set of human chroms.

Question 4

Whole-genome shotgun approach

Answer 4

attempt to sequence the human genome by cloning and sequencing DNA fragments from randomly cut DNA
o Computer programs combine these into a continuous sequence

Question 5

Metagenomics

Answer 5

approach in which DNA from an entire group of species is collected from an environmental sample and sequenced

Question 6

Gene annotation

Answer 6

when scientists are able to identify all the protein-coding genes in the sequence and their functions
o Involves looking for expressed tag sequences

Question 7

Expressed sequence tags (Gene annotation)

Answer 7

using a software to scan stored sequences for transcriptional and translational start and stop signals, RNA splicing sites, and other signs of protein coding genes
• This software looks for short sequences that specify known mRNA’s
• Identifies sequences that turn out to be previously unknown protein-coding genes
• Collected from cDNA sequences

Question 8

Proteomics

Answer 8

the systematic study of proteins and their properties
o	Proteins (not the genes that encode them) carry out most of the activities in the cell.

Question 9

Systems biology (defn and uses)

Answer 9

aims to model the dynamic behavior of whole biological systems based on the study of the interactions among a system’s parts
o Used to
• Define gene and protein interaction networks
• Map gene products in specific locations based on the similarity of their interactions

Question 10

Pseudogenes

Answer 10

former genes that have accumulated mutations over a long time and no longer produce functional proteins
o Single copy, noncoding DNA

Question 11

repetitive DNA

Answer 11

consists of sequences that are present in multiple copies of the genome

Question 12

junk DNA

Answer 12

noncoding DNA that neither codes for proteins nor is transcribed to produce RNA’s with known functions

Question 13

transposable elements

Answer 13

stretches of ‘noncoding’ DNA that can move from one location to another within the genome
o Never completely detach from the DNA

Question 14

transposition

Answer 14

when a transposable element moves from one site in cell’s DNA to a different target site by a type of recombination

Question 15

transposons

Answer 15

eukaryotic transposable elements that move within a genome by means of a DNA intermediate

Question 16

transposase

Answer 16

enzyme encoded by transposon

Question 17

retrotransposons

Answer 17

move by means of RNA intermediate that is transcript of retrotransposon DNA
• Leave a copy at original site
• RNA intermediate is first converted back to DNA by reverse transcriptase (which is coded by retrotransposon)

Question 18

Alu elements

Answer 18

transposable element-related DNA which do not code for any protein
o Some Alu elements are transcribed into RNAs which regulate gene expression

Question 19

simple sequence DNA

Answer 19

contains many copies of tandemly repeated short sequences
o Makes up 3% of human genome
o Ex: GTTAC/ GTTAC/ GTTAC

Question 20

short-tandem repeat

Answer 20

when a unit contains a set of 2-5 nucleotides

Question 21

multigene families

Answer 21

groups of genes from the same organism that code proteins with similar sequences
o In MG families consisting of identical DNA sequences, sequences are clustered tandemly and have RNA as final products
o In MG families with nonidentical genes, the different forms of the subunit are expressed at different times during the development, allowing the function of the protein
o Ex. Alpha and beta hemoglobin

Question 22

polyploidy

Answer 22

accident in meiosis which results in one or more extra sets of chromosomes

Question 23

exon shuffling

Answer 23

occasional mixing and matching of different exons either within a gene or between two different genes
o Happens as a result of errors in meiotic recombination
o Could lead to proteins with new combinations of functions

Question 24

highly conserved

Answer 24

genes which have remained similar in distantly related species

Question 25

SNP’s (single nucleotide polymorphisms)

Answer 25

singe base-pair sites where variation is found in at least 1% of the population

Question 26

copy-number variants

Answer 26

loci where some individuals have one or multiple copies of a particular gene or genetic region (rather than the standard 2 copies)

Question 27

evo-devo

Answer 27

field in which biologists compare developmental processes of different multicellular organisms
o The want to understand how processes have evolved and how changes can modify existing organismal features or lead to new ones

Question 28

homeobox

Answer 28

a 180-nucleotide sequence which codes for a 60-amino-acid homeodomain in the encoded proteins

Question 29

homeodomain

Answer 29

o 180-nucleotide sequence

o Found in genes which regulate anatomical development (morphogenesis)