Micro Chapter 9

Front 1

Adenine

Back 1

Portrayed as “A”. One of the nitrogen bases found in DNA and RNA, with a purine form.

Front 2

Ames test

Back 2

A method for detecting mutagenic and potentially carcinogenic agents based upon the genetic alteration of nutritionally defective bacteria.

Front 3

Anticodon

Back 3

The trinucleotide sequence of transfer RNA that is complementary to the trinucleotide sequence of messenger RNA (the codon).

Front 4

Antiparallel strands

Back 4

one strand of DNA runs from 5’ to 3’ and the other runs from 3’ to 5’. Native double stranded DNA always has the anitparallel configuration. (Raven)

Front 5

Back-mutation

Back 5

A mutation that counteracts an earlier mutation, resulting in the restoration of the original DNA sequence.

Front 6

Base Substitution Mutation

Back 6

The substitution of one base pair for another in DNA. [Slide 39 - Three kinds are: Missense, Nonsense and Silent. ]

Front 7

Chargaff’s Rules

Back 7

basically that adenine (A) binds to thymine (T) with 2 hydrogen bonds. And guanine (G) binds to cytosine (C) with 3 hydrogen bonds. (It then follows that when the original two strands split, each is able to make an exact copy of the part that just split away.) 3/13

Front 8

Chromosomes

Back 8

The tightly coiled bodies in cells that are the primary sites of genes. (Most bacteria have only one and it is circular because they have trouble copying the ends of DNA. 3/13.)

Front 9

Conjugation

Back 9

In bacteria, the contact between donor and recipient cells associated with the transfer of genetic material such as plasmids. Can involve special (sex) pili. Also a form of sexual recombination in ciliated protozoans. [Slide 43 – transfer of a plasmid or chromosomal fragment from a donor cell to a recipient cell via a direct connection.]

Front 10

Cytosine

Back 10

Portrayed as “C”. One of the nitrogen bases found in DNA and RNA, with a pyrimidine form.

Front 11

Deoxyribose Sugar

Back 11

A 5-carbon sugar that is an important component of DNA.

Front 12

DNA

Back 12

Deoxyribonucleic acid (DNA) - The nucleic acid often referred to as the “double helix.” DNA carries the master plan for an organism's heredity.

Front 13

DNA polymerase

Back 13

[Slide 10 - A class of enzymes that all synthesize DNA from a preexisting template. All synthesize only in the 5’ to 3’ direction and require a primer to extend. (Raven) DNA polymerase III – adds nucleotides in a 5’ to 3’ direction with the leading strand and lagging strand concept. DNA polymerase I – removes the RNA primers and replaces them with DNA.] [Slide 40 – proofreads nucleotides during DNA replication.]

Front 14

fertility (F′) factor - Donor plasmid that allows synthesis of a pilus in bacterial conjugation. Presence of the factor is indicated by F+, and lack of the factor is indicated by F−.

Back 14

Fertility

Front 15

Frameshift mutation - An insertion or deletion mutation that changes the codon reading frame from the point of the mutation to the final codon. Almost always leads to a nonfunctional protein.

Back 15

Frameshift

Front 16

Gene

Back 16

A site on a chromosome that provides information for a certain cell function. A specific segment of DNA that contains the necessary code to make a protein or RNA molecule. [Slide 4 - The fundamental unit of heredity responsible for a given trait. 3/13]

Front 17

Genome

Back 17

The complete set of chromosomes and genes in an organism.

Front 18

Genotype

Back 18

The genetic makeup of an organism. The genotype is ultimately responsible for an organism's phenotype, or expressed characteristics. [Slide 5 - All the types of genes that constitute the genetic makeup. 3/13]

Front 19

Guanine

Back 19

One of the nitrogen bases found in DNA and RNA in the purine form.

Front 20

[Slide 10] Any of a group of enzymes that unwind the two strands in the double helix to facilitate DNA replication. (Raven) 3/13

Back 20

Helicase

Front 21

Induced mutations

Back 21

Any alteration in DNA that occurs as a consequence of exposure to chemical or physical mutagens. [Slide 38 – result from exposure to known mutagens, physical (primarily radiation) or chemical agents that interact with DNA in a disruptive manner.]

Front 22

Inducible operon

Back 22

[Slide 33 – Operon is turned ON by substrate: catabolic operons – enzymes needed to metabolize a nutrient are produced when needed.]

Front 23

Introns

Back 23

[Slide 30 – Eukaryote DNA contains these intervening sequences of noncoding DNA which have to be splices out of the final mRNA transcript.]

Front 24

One of the carbohydrates commonly referred to as sugars. Lactose is commonly found in milk.

Back 24

Lactose

Front 25

Control system that manages the regulation of lactose metabolism. It is composed of three DNA segments, including a regulator, a control locus, and a structural locus.

Back 25

Lactose (lac) operon

Front 26

[Slide 11] DNA ligase – When replication forks meet, DNA ligase links together the DNA fragments in the lagging strand to complete synthesis.

Back 26

Ligase

Front 27

A single-stranded transcript that is a copy of the DNA template that corresponds to a gene. [Slide 18- carries DNA message through complementary copy; message is in triplets called codons.]

Back 27

Messenger RNA(MRNA)

Front 28

A mutation in which a change in the DNA sequence results in a different amino acid being incorporated into a protein, with varying results. [Slide 39 – causes change in a single mutation.]

Back 28

Missense mutation

Front 29

Any agent that induces genetic mutation. Examples: certain chemical substances, ultraviolet light, radioactivity.

Back 29

Mutagens

Front 30

A subspecies of microorganism that has undergone a mutation, causing expression of a trait that differs from other members of that species. [Slide 37 – An organism that has a mutation is a mutant strain, showing variance in morphology, nutritional characteristics, genetic control mechanisms, resistance to chemicals, etc.]

Back 30

Mutant strain

Front 31

A permanent inheritable alteration in the DNA sequence or content of a cell. [Slide 37 – A change in phenotype due to a change in genotype (nitrogen base sequence of DNA).]

Back 31

Mutation

Front 32

Nitrogenous base

Back 32

A nitrogen-containing molecule found in DNA and RNA that provides the basis for the genetic code. Adenine, guanine, and cytosine are found in both DNA and RNA, whereas thymine is found exclusively in DNA and uracil is found exclusively in RNA.

Front 33

Nonsense codons

Back 33

A triplet of mRNA bases that does not specify an amino acid but signals the end of a polypeptide chain. Also called stop codon.

Front 34

Nonsense mutation

Back 34

A mutation that changes an amino acid-producing codon into a stop codon, leading to premature termination of a protein. [Slide 39 – changes a normal codon into a stop codon.]

Front 35

Nucleotide

Back 35

The basic structural unit of DNA and RNA; each nucleotide consists of a phosphate, a sugar (ribose in RNA, deoxyribose in DNA), and a nitrogenous base such as adenine, guanine, cytosine, thymine (DNA only) or uracil (RNA only).

Front 36

In an operon sequence, the DNA segment where transcription of structural genes is initiated.

Back 36

Operator

Front 37

A genetic operational unit that regulates metabolism by controlling mRNA production. In sequence, the unit consists of a regulatory gene, inducer or repressor control sites, and structural genes. [Slide 32 – In prokaryotes regulation is coordinated by operons, a set of genes, all of which are regulated as a single unit (eukaryotes do not have operons).]

Back 37

Operon

Front 38

Phenotype

Back 38

The observable characteristics of an organism produced by the interaction between its genetic potential (genotype) and the environment. [Slide 5 - The expression of the genotype that produces observable traits. 3/13]

Front 39

Phosphate

Back 39

An acidic salt containing phosphorus and oxygen that is an essential inorganic component of DNA, RNA, and ATP.

Front 40

Pilus (singular, pilus)

Back 40

Small, stiff filamentous appendages in gram-negative bacteria that function in DNA exchange during bacterial conjugation.

Front 41

Point Mutations

Back 41

A change that involves the loss, substitution, or addition of one or a few nucleotides.

Front 42

Primase

Back 42

[Slide 10] The enzyme that synthesizes the RNA primers required by DNA polymerases. (Raven) 3/13

Front 43

Promoter

Back 43

Part of an operon sequence. The DNA segment that is recognized by RNA polymerase as the starting site for transcription.