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Genetics

Study of inheritance and inheritable traits as expressed in an organism's genetic material

Genome

The entire genetic complement of an organis. Includes its genes and nucleotide sequences

Prokaryotic chromosomes

Main portion of DNA, along with associated proteins and RNA

Haploid

Prokaryotic cells are _____(single chromosome copy)

Circular

Typical chromosome of prokaryote is _____molecule of DNA in nucleoid

Plasmids

Small molecules of DNA that replicate independently; Not essential for normal metabolism, growth, or reproduction

Fertility factors, Resistance factors, Bacteriocin factors, Virulence plasmids

types of plasmids

DNA Replication

Anabolic polymerization process that requires monomers and energy.

Triphosphate deoxyribonucleotides

_______ _______ serve both functions in structure and replicating genomes.

Complementary

Key to replication is ______ structure of the two strands

Replication

________ is semiconservative . New DNA composed of one original and one daughter strand.

Origin

Bacterial DNA replication begins at the _____.

5' to 3'

DNA polymerase replicates DNA only _____.

Antiparallel

Because strands are_____, new strands are synthesized differently

Leading strand

The strand synthesized continuously

Lagging strand

The strand synthesized discontinuously

bidirectional

DNA replication occurs________.

Topoisomerases

remove supercoils in DNA molecule

Methylated

DNA is ______.Control of genetic expression; Initiation of DNA replication; Protection against viral infection; Repair of DNA

Replication of eukaryotic DNA

Uses four DNA polymerases; Thousands of replication origins; Shorter Okazaki fragments; Plant and animal cells methylate only cytosine bases

Genotype

Set of genes in the genome

Phenotype

Physical features and functional traits of the organism

Transcription

Information in DNA is copied as RNA

Translation

Polypeptides synthesized from RNA

RNA; polypeptides

Central dogma of genetics; DNA transcribed to ____ and it is translated to form ______.

RNA primers, mRNA, rRNA, and tRNA

Four types of RNA transcribed from DNA

Nucleus, mitochondria, and chloroplasts

In eukaryotes, RNA transcription occurs in the _____, ______, and ______.

Polymerase and transcription

In eukaryotes there are three types of RNA ___________and numerous __________ factors.

Translation; capping, polyadenylation and splicing

mRNA is processed before ______ by:

Translation

Process where ribosomes use genetic information of nucleotide sequences to synthesize polypeptides

Messenger RNA; Transfer RNA; Ribosomes and ribosomal RNA

Participants in translation

Termination

Stage of translation when release factors recognize stop codons; Modify ribosome to activate ribozymes

Subunits

In termination, ribosome dissociates into _____.

Polypeptides

_______ released at termination may function alone or together

75%

____ of genes are expressed at all times;

Conserve energy

Other genes transcribed and translated when cells need them. This allows the cell to ____ ____.

Regulation of protein synthesis

Typically halts transcription; Can stop translation directly

Operon

An _____ consists of a promoter and a series of genes

Operator

Some operons are controlled by a regulatory element called an ______.

Inducible

_____operons must be activated by inducers

Lactose operon

Example of inducible operon

Repressible

______ operons are transcribed continually until deactivated by repressors

Tryptophan operon

An example of a repressible operon

Mutation

Change in the nucleotide base sequence of a genome; Rare event; Almost always deleterious

Mutations ______ leads to a protein that improves ability of organism to survive.

rarely

Point mutations

Most common mutation where one base pair is affected and it occurs in insertions, deletions, and substitutions.

Frameshift mutations

Nucleotide triplets after the mutation are displaced and results in insertions and deletions.

Radiation

Mutations can occur from ______, for example ionizing radiation and nonionizing radiation.

Chemical mutagens

Mutation that occurs nucleotide analogs; Disrupt DNA and RNA replication.

Nucleotide-altering chemicals

Result in base-pair substitutions and missense mutations

Frameshift mutagens

Result in nonsense mutations

Rare

Mutations are ____ events; Otherwise organisms could not effectively reproduce

Mutagens

________ increase the mutation rate by a factor of 10 to 1000 times

Mutants

Descendents of a cell that does not repair a mutation

Wild types

Cells normally found in nature

Positive selection, negative (indirect) selection and Ames test

Methods to recognize mutants

Homologous

Exchange of nucleotide sequences often mediated by _____sequences.

Recombinants

Cells with DNA molecules that contain new nucleotide sequences

Vertical gene transfer

Organisms replicate their genomes and provide copies to descendants

Horizontal gene transfer

Donor cell contributes part of genome to recipient cell

Transformation, transduction, and bacterial conjugation

Three types of horizontal gene transfer among prokaryotes

Transformation

One of conclusive pieces of proof that DNA is genetic material

Competent

Cells that take up DNA are _____. Results from alterations in cell wall and cytoplasmic membrane that allow DNA to enter cell

Generalized Transduction

Transducing phage carries random DNA segment from donor to recipient

Specialized transduction

Only certain donor DNA sequences are transferred

Transposons

Segments of DNA that move from one location to another in the same or different molecule

Transpositions

Result of transposons is a kind of frameshift insertion (_______)

Palindromic

Transposons all contain ________ sequences at each end

Genes

__ are composed of specific sequences of nucleotides that code for poylpeptides or RNA molecules

Genome

__ is the sum of all the genes and linking nucleotide sequences in a cell or virus.

Base pairs (bp)

the two strands of DNA are held together by hydrogen bonds between complementary __ ___ of nucleotides. Adenine bonds with thymine, and guanine bonds with cytosine

Chromosomes; nucleoid

bacterial and archaeal genomes consist of one ____, which are typically circular molecules of DNA associated with protein and RNA molecules, localized in a region of the cytosol called the ___

Histones

Archaeal DNA organizes around globular proteins called ___.

Plasmids

Prokaryotic cells may also contain one or more extra chromosomal DNA molecules called ___, which contain genes that regulate nonessential life functions, such as bacterial conjugation and resistance to antibiotics

Each newly synthesized strand of DNA remains associated with one of the parental strands

DNA replication is semiconservative

Leading strand; lagging strand

After helicase unwinds and unzips the original molecule, synthesis of each of the two daughter strands- called the ___ and the ___- occurs from 5' to 3'. Synthesis is mediated by enzymes that prime, join, and proofread the pairing of new nucleotides

Methylation

After DNA replication, ___ occurs.

Methylation

___ plays several roles, including the control of gene expression, the initiation of DNA replication, recognition of a cell's own DNA, and repair.

Genotype; phenotype

The ___ of an organism is the actual set of genes in its genome, whereas its ___ refers to the physical and functional traits expressed by those genes

RNA primer; messenger RNA; tRNA; rRNA

RNA has several forms. These include ___; ____, which carries genetic information from DNA to a ribosome; ___, which carries amino acids to the ribosome, and ___, which, together with polypeptides, makes up the structure of ribosomes

Central dogma

The ___ of genetics states that genetic information is transferred from DNA to RNA to polypeptides, which function alone or in conjunction as proteins

Transcription; RNA polymerase

The transfer of genetic information begins with ___ of the genetic code from DNA to RNA, in which ___ links RNA nucleotides that are complementary to genetic sequences in DNA.

Promoter; terminator

Transcription begins at a region of DNA called a ___ and ends with a sequence called a ___. In bacteria, Rho protein may assist in termination, or termination may depend solely on the nucleotide sequence of the transcribed RNA

Introns; exons

eukaryotic mRNA is synthesized as pre-messenger RNA. Before translation can occur, a spliceosome removes noncoding ___ from pre-mRNA and splices together the ___, which are the coding sections

Translation

In ___, the sequence of genetic information carried by mRNA is used by ribosomes to construct polypeptides with specific amino acid sequences

Codons; anticodons

The genetic code consists of triplets of mRNA nucleotides, called ___. These bind with complementary ___ on transfer RNAs.

tRNA

___ are molecules that carry specific amino acids

Ribosomal RNA

___ catalyzes the bonding of one amino acid to another to form a polypeptide.

Amino acids

A sequence of nucleotides thus codes for a sequence of ___ ___.

Operon; operator

an __ is a series of prokaryotic genes, a promoter, and in some cases an ___ sequence, all controlled by one regulatory gene.

Inducible operons

___ are normally "turned off" and are activated by inducers that block repressors from binding to the operator.

Repressible operons

___ are normally "on" and are deactivated by repressors that bind to the operator

Mutation

a ___ is a change in the nucleotide base sequence of a genome.

Point mutations; substitutions; frameshift mutations

___ involve a change in a nucleotide base pair and include ___ and two types of ____

Insertions and deletions

two types of frameshift mutations

Silent, missense, nonsense mutations

Mutations can be categorized by their effects as ___, ___, or ___

Mutagens

physical or chemical agents called ___ can increase the normal rate of mutation.

Mutants; wild-type; positive selection, negative (indirect) selection, Ames test; carcinogens

Researchers have developed methods to distinguish ___, which carry mutations, from normal ___ cells. These methods include ___, ___, and the ___, which is used to identify mutagens, which may be potential ____

Genetic recombination

organisms acquire new genes through ___, which is the exchange of segments of DNA. Crossing over occurs during gamete formation, part of sexual reproduction in eukaryotes

Horizontal (lateral) gene transfer; donor cell; recipient cell

Vertical gene transfer is the transmission of genes from parents to offspring. In ___, DNA from a ___ is transmitted to a ____.

Recombinant cell

A ___ results from genetic recombination between donated and recipient DNA.

Transformation, transduction and bacterial conjugation

___, ___, and __ are types of horizontal gene transfer

Transformation; competent

In ___ a ___ recipient prokaryote takes up DNA from its environment. Competency is found naturally or can be created artificially in some cells

Transduction; bacteriophage; phage

In ___, a virus such as __, or ___, carries DNA from a donor cell to a recipient cell

Transducing phages

Donor DNA is accidentally incorporated in such ___ ___

Conjugation ; F (fertility) plasmid (factor); conjugation pilus

In ___, an F+ bacterium -that is, one containing an _____- forms a ____ that attaches to an F- recipient bacterium . Plasmid genes are transferred to the recipient, which becomes F+ as a result

Transposons; inverted repeats (IR); transposition; insertion sequences (IS); Complex transposons

___ are DNA segments that code for the enzyme transposase and have palindromic sequences known as ___ at each end. Transposons move among locations in chromosomes in eukaryotes and prokaryotes- a process called ___. The simplest transposons, known as ___, consist only of inverted repeats and transposase. ___ contain other genes as well.

a. 4,000,000

which of the following is most likely the number of base pairs in a bacterial chromosome?
a. 4,000,000
b. 4000
c. 400
d. 40

c. they are located in the cytosol

which of the following is a true statement concerning prokaryotic chromosomes?
a. they typically have two or three origins of replication
b. they contain single-stranded DNA
c. they are located in the cytosol
d. they are associated in linear pairs

d. extra chromosomal DNA

a plasmid is __

c. histone

which of the following forms ionic bonds with eukaryotic DNA and stabilizes it?
a. chromatin
b. bacteriocin
c. histone
d. nucleosome

carry energy.
are found in four forms, each with a deoxyribose sugar, a phosphate, and a base
are present in the cytosol of cells as triphosphate nucleotides

Nucleotides used in the replication of DNA ___

a. DNA polymerase III

which of the following molecules function as a "proofreader" for a newly replicated strand of DNA?
a. DNA polymerase III
b. primase
c. helicase
d. ligase

a. methylation

the addition of -CH3 to a cytosine nucleotide after DNA replication is called ___

d. E site

in translation, the binding site through which tRNA molecules leave is called the ___

uses auxotrophs and liver extract to reveal potential mutagens

The Ames test ____

c. transcription

which of the following is NOT a mechanism of natural genetic transfer and recombination?
a. transduction
b. transformation
c. transcription
d. conjugation

d. competent

Cells that have the ability to take up DNA from their environment are said to be ___

a. conjugation requires a sex pilus extending from the surface of a cell

Which of the following statements is true?
a. conjugation requires a sex pilus extending from the surface of a cell
b. conjugation involves a Cfactor
c. conjugation is an artificial genetic engineering technique.
d.conjugation involves DNA that has been released into the environment from dead organisms

d. transponsons

which of the following are called "jumping genes"?
a. Hfr cells
b. transducing phages
c. palindromic sequences
d. transponsons

c horizontal gene transfer

although cells P and Q are totally unrelated, cell Q receives DNA from cell P and incorporates this new DNA into it chromosome. This process is ___

b. codon

which of the following is part of each molecule of mRNA?
a. palindrome
b. codon
c. anticodon
d. base pair

a five-carbon sugar
phosphate
a nitrogenous base

a nucleotide is composed of ___

two/thymine

in DNA, adenine forms __ hydrogen bonds with ___

an Okazaki fragment

a sequence of nucleotides formed during replication of the lagging DNA strand is __

c. origin

which of the following is NOT part of an operon?
a. operator
b. promoter
c. origin
d. gene

RNA transcription

repressible operons are important in regulating prokaryotic ___

RNA molecules

transcription produces ___

lagging strand replication

ligase plays a major role in ___

lasting
beneficial
inheritable

before mutations can affect a population permanently, they must be ___

active/ a repressor

the trp operon is repressible. This means it is usually ___ and is directly controlled by ___

initiation of transcription, elongation of the RNA transcript, termination of transcrition

The three steps in RNA transcription are __, __, and ___.

codon

a triplet of mRNA nucleotides that specifies a particular amino acid is called a ___

silence, missense, nonsense

Three effects of point mutations are ___, ___, and ___

frameshift

insertions and deletions in the genetic code are also called ___ mutations

promoter, operator, a series of genes

an operon consists of ___, ____, and ___ and is associated with a regulatory gene

inducible

in general, ___ operons are inactive until the substrate of their genes' polypeptides is present

semiconservative

a daughter DNA molecule is composed of one original strand and one new strand because DNA replication is ____

transformation, transduction, bacterial conjugation

A gene for antibiotic resistance can move horizontally among bacterial cells by ___, ___, and ____

transposons

___ are nucleotide sequences containing palindromes and genes for proteins that cut DNA strands.

crossing over

____ ____ is a recombination event that occurs during gamete formation in eukaryotes

transfer

___ RNA carries amino acids

short interference, micro

___ RNA and ___ RNA are antisense; that is, they are complementary to another nucleic acid molecule

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