Ch. 7 DNA Structure and Gene Function LearnSmart

eukaryotic protein production

1 inside the nucleus, an enzyme transcribes a gene's DNA sequence to a complementary sequence of RNA 2 the RNA is modified 3 the RNA moves out of the nucleus and binds to a ribosome 4 at the ribosome, amino acids are assembled in a specific order to produce protein

transcription initiation

1. a transcription factor binds to the TATA box of the promoter 2. the TATA binding protein attracts other transcription factors 3. transcription factors bound at enhancers and the promoter form a complex 4. RNA polymerase is able to bind to the promoter at the start of the gene and begin transcription

initiation of translation

1. mRNA leader sequence bonds with small ribosomal subunit 2. tRNA with UAC anticodon binds to AUG start codon 3. methionine is in place at the beginning of the polypeptide, and the large ribosomal subunit attaches to the small subunit

translation

1. the 5' end of the mRNA molecule binds with the small ribosomal subunit 2. the first tRNA binds to the start codon on the mRNA molecule 3. the large ribosomal subunit binds to the small ribosomal subunit 4. the second tRNA molecule binds to the second codon on the mRNA molecule 5. a covalent bond is formed between the two amino acids 6. the ribosome releases an empty tRNA

the mRNA sequence _____ codes for the amino acid sequence Met-Trp-Arg

AUGUGGAGG

the information that each cell needs to produce proteins is stored in a molecule called

DNA

select all the statements about nucleotides that are accurate

DNA always contains the same sugar in its nucleotides, they are the building blocks of DNA and RNA, and they are composed of a sugar, a nitrogen-containing group, and one or more phosphorus-containing groups

during transcription, what reads the template strand within a gene and adds complementary bases?

RNA polymerase

initiation

RNA polymerase binds to the gene's promoter

elongation

RNA polymerase moves down the template strand, adding nucleotides and producing a complementary RNA molecule

termination

RNA polymerase separates from the DNA and the newly synthesized RNA is released

in transcription, a(n) _____ molecule is produced from the information that is encoded in a(n) _____ molecule

RNA; DNA

frameshift

adds or deletes nucleotides in any number other than a multiple of three

the term genome refers to

all the genetic material in an organism's cell

on a tRNA molecule, the _____ is a three-base sequence that is complementary to and binds to an mRNA codon during translation

anticodon

select all of the following that are true about frameshift mutations

can be caused by the deletion of two nucleotides, likely to change the amino acid sequence, disrupts the codon reading frame, and can be caused by the addition of one nucleotide

in an RNA molecule, a(n) _____ is a genetic "code word" that corresponds to one amino acid

codon

tRNA

contains an anticodon on one end that determines what amino acid binds to the other end

mRNA

contains codons specifying the order of amino acids

during the elongation phase of translation, a _____ bond is formed between the incoming _____ acid and the growing polypeptide chain, and empty tRNAs are released from the ribosome to be reused.

covalent; amino

hershey and chase

demonstrated that radioactively-labeled DNA, not protein, entered bacterial cells and directed them to produce viruses

erwin chargaff

determined that DNA contains equal amounts of adenine and thymine and of guanine and cytosine

avery, mccarty, and macleod

discovered that DNA was the transforming principle

griffith

discovered that one strain of bacteria could "transform" another by inducing it to display new traits

garrod

discovered that people with "inborn errors of metabolism" lacked certain enzymes

_____ are portions of mRNA that get spliced together to form mature mRNA prior to translation

exons

select all the reasons a cell regulates gene expression

helps orchestrate organism development, to have a specialized function, and to respond to changing conditions

a(n) _____ is a portion of RNA that averages about 1,000 nucleotides long and that is removed before translation

intron

transcription of the three genes in the lac operon occurs when

lactose is present in the environment and binds to the repressor

the lac operon in E. coli bacteria includes three genes that produce

lactose-degrading enzymes

each ribosome has one _____ subunit and one _____ subunit that join at the initiation of protein synthesis

large; small

because ribosomes cannot "read" a gene directly, the genetic information to make a protein is "transcribed" into a(n) _____ molecule, which in turn is "translated" by the ribosome to make a _____ molecule

mRNA; protein

rRNA

major component that makes up the structure of a ribosome

a(n) _____ is a change in a cell's DNA sequence

mutation

silent

mutation that encodes the same protein as the original gene version

missense

mutation that results in the change of a codon for one amino acid into a codon for another

nonsense

mutation that results in the creation of a stop codon

which of the following describes a substitution mutation?

one DNA base is replaced with another

in bacterial operons, if repressor protein binds to a sequence on the DNA called a(n) _____, transcription is inhibited

operator

a _____ is a sequence of DNA that signals the start of a gene and is the site where RNA polymerase binds to begin transcription

promoter

eukaryotic and prokaryotic

proteins to bind to regulatory sequences within DNA and controlling access to a promoter

select all of the following that are mutagens

radioactive fallout, ultraviolet radiation, harmful chemicals, and chemicals in tobacco

in the hershey and chase experiment, _____ was found inside the infected bacteria indicating that the labeled viral _____ had entered the bacterial cells to direct new virus production

radioactive phosphorus; DNA

a complex of rRNA and proteins called a(n) _____ is the physical location of protein synthesis

ribosome

select all of the following that are genes

sequence of DNA nucleotides that codes for a specific protein and sequence of DNA nucleotides that codes for a specific RNA molecule

a substitution mutation is said to be _____ if the mutated gene encodes the same protein as the original gene version

silent

which of the following agents or processes can cause mutations?

some forms of radiation, chemical mutagens, and DNA replication

eukaryotic cells

splicing RNA and RNA processing, adding methyl groups to silence genes, and enhancers

select all of the following that are true about codons

tRNAs haave specific complementary sequences that bind to them, they are found in mRNA, and they are composed of three mRNA bases

select all the ways that cells can make DNA less available for transcription

tag DNA with methyl groups and wind DNA more tightly

a specific sequence on the DNA called a(n) _____ sequence signals the end of a gene during transcription

terminator

which of the following best describes translation?

the "reading" of an mRNA to produce a protein

select all of the following that are true about the genetic code

the same genetic code is used by nearly all species, three codons are "stop" codons, and AUG encodes methionine and "start"

in eukaryotic cells, proteins called _____ factors bind at specific DNA sequences, which allows RNA polymerase to initiate transcription

transcription

in the "central dogma" describing the flow of genetic information from DNA to protein, DNA is copied to RNA in a process called _____, and the information in RNA is used to direct the synthesis of a protein in a process called _____

transcription; translation

select all of the following that are examples of large-scale mutations, which are mutations that affect extensive regions of DNA

translocation of one chromosome region to another chromosome, inversion of a chromosome arm, and duplication of chromosome region

james watson and francis crick

used the known ratios of nucleotides along with the x-ray diffraction data to build a ball-and-stick model of the DNA double helix

maurice wilkins and rosalind franklin

used x-ray diffraction to determine the three dimensional shape of the DNA molecule

what scientists worked out the double helical structure of DNA using a ball-and-stick model?

watson and crick