Lesson 8 Definitions

Question 1

DNA

Answer 1

polymer made from repeating nucleotide units

Question 2

Nucleotides

Answer 2

made of a nucleobase, a deoxyribose sugar, and a phosphate group

Question 3

Hydrogen bonds

Answer 3

link nucleobase pairs together: adenine pairs with thymine, cytosine pairs with guanine

Question 4

codon

Answer 4

nucleotide triplets are “code words” for amino acids, genes contain instructions for making proteins

Question 5

PCR

Answer 5

(polymerase chain reaction) l

Question 6

gene inversion

Answer 6

order of a particular group of genes is reversed

Question 7

gene duplication

Answer 7

group of genes is duplicated

Question 8

gene translocation

Answer 8

information from one of two homologous chromosomes breaks and binds to the other, most likely to be lethal

Question 9

nucleotide deletion

Answer 9

removal of nucleotide causes remainder of sequence to be out of place

Question 10

nucleotide insertion

Answer 10

addition of nucleotide causes remainder of sequence to be out of place (also called frameshift mutation)

Question 11

nucleotide inversion

Answer 11

portion of nucleotide sequence is reversed, not as lethal as insertion or deletion

Question 12

nucleotide substitution

Answer 12

replacement of a nucleotide. Not as harmful as insertion/deletion; cause of sickle cell anemia, antibiotic resistance in some bacteria

Question 13

spontaneous mutation

Answer 13

a mutation occurring in the absence of mutagens, usually due to errors in the normal functioning of cellular enzymes.

Question 14

induced mutation

Answer 14

a mutation caused by mutagens, such as chemicals, radiation, or viral infections

Question 15

neutral mutation

Answer 15

majority of mutations, neither harmful or beneficial

Question 16

positive selection

Answer 16

(Darwinian selection)

Question 17

nucleobase

Answer 17

nitrogen-containing biological compounds that form nucleosides, which, in turn, are components of nucleotides, with all of these monomers constituting the basic building blocks of nucleic acids

Question 18

RNA

Answer 18

ribonucleic acid, a nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins, although in some viruses RNA rather than DNA carries the genetic information

Question 19

anticodon

Answer 19

a sequence of three nucleotides forming a unit of genetic code in a transfer RNA molecule, corresponding to a complementary codon in messenger RNA

Question 20

DNA replication

Answer 20

the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the most essential part for biological inheritance

Question 21

helicase

Answer 21

enzymes that bind and may even remodel nucleic acid or nucleic acid protein complexes

Question 22

DNA binding protein

Answer 22

proteins that have DNA-binding domains and thus have a specific or general affinity for single- or double-stranded DNA

Question 23

DNA polymerase

Answer 23

a member of a family of enzymes that catalyze the synthesis of DNA molecules from nucleoside triphosphates, the molecular precursors of DNA. These enzymes are essential for DNA replication and usually work in groups to create two identical DNA duplexes from a single original DNA duplex.

Question 24

mutagen

Answer 24

an agent, such as radiation or a chemical substance, which causes genetic mutation.

Question 25

transcription factor

Answer 25

a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence

Question 26

RNA polymerase

Answer 26

a multi-unit enzyme that synthesizes RNA molecules from a template of DNA through transcription

Question 27

tRNA

Answer 27

transfer RNA

Question 28

mRNA

Answer 28

messenger RNA

Question 29

ribosomal subunit

Answer 29

required for translation

Question 30

protein translocation

Answer 30

after the protein is formed, it is transported to other parts of the cell

Question 31

translocon

Answer 31

complex of proteins associated with transport of proteins across membranes

Question 32

signal sequence

Answer 32

short amino acid sequence on some proteins that acts as a “zip code” for the target organelle

Question 33

DNA ligase

Answer 33

attaches Okazaki fragments together

Question 34

topoisomerase

Answer 34

unwinds DNA