BIO-110 Chapter 6

DNA and RNA are the…..

two types of nucleic acids that store information

DNA is a ______ which is a large molecule made of repeating smaller units which are ______

polymer, nucleotides

DNA polymers can be _____ ______ or tightly wrapped ______

long fibers, chromosomes

The structure of DNA has a ____ _____, ______ bonds holding the base pairs and ______ bonds holding the backbone. The chemical structure of the ______ is common to all life on earth.

double helix, hydrogen, covalent, backbone

Every molecule of DNA is made from subunits called

nucleotides

A

deoxyribose sugar

B

phosphate

C

base made from one or two rings of nitrogen/carbon

the sugar and phosphate of DNA is ______ amongst all DNA nucleotides

identical

One molecule of DNA contains _____ polynucleotides

two

DNA has an overall ______ charge

negative

What is DNA replication?

the process by which a cell makes exact copies of its DNA

DNA is semi conservative meaning…

each strand has one that is newly created and one that is original

A

replication fork

B

DNA polymerase

C

helicase

D

lagging strand

E

leading strand

A

transcription

B

translation

C

DNA

D

RNA

E

protein

Under the direction of DNA, _____ carries instructions that result in the production of proteins

RNA

Structural difference between DNA and RNA

• double helix vs single strand

• sugars in DNA are deoxyribose vs ribose in RNA

• DNA has base thymine, while RNA has base uracil

DNA produces and _____, RNA controls the ______, Proteins perform the ______ of cellular functions

directs, manufacture, majority

Transcription begins when the _____ in a nucleus directs the _______ of RNA, specifically ______ which is _______ RNA

DNA, production, mRNA, messenger

DNA base pair Thiamine pairs to mRNA Adenine, while DNA base pair ______ pairs to _____ in mRNA

adenine, uracil

Codons do what?

specifies a particular amino acid or peptide

A long chain of amino acids is called _______

polypeptide

Molecular chain of command is…

DNA makes RNA, which makes proteins, they control your physical traits

What does RNA polymerase do in transcription?

it binds to a DNA sequence and signals to the gene to “start here”

By controlling whether or not RNA polymerase can bind the promoter, a cell can turn a gene…..

on or off

After RNA polymerase binds at the promoter, it ____ open the double helix of ____. One strand serves as a template for the formation of ____; the other is unused.

peels, DNA, RNA

Transcription ends when RNA polymerase reaches a DNA _____ sequence which is called a _____

stop, terminator

Introns

regions that do not encode for amino acids

Exons

regions that do code for amino acids

This occurs when a growing RNA molecule has its introns removed by an enzyme so that way, only the exons remain

RNA splicing

What is a gene?

a unit of hereditary information consisting of a specific nucleotide sequence in DNA

Why might a molecule of mRNA be shorter than the gene from which it is derived?

its introns are removed and the molecule is shorter

________ takes place within the cytoplasm in cellular structures called _____

translation, ribosomes

Ribosomes themselves are made from proteins combined with a special type of RNA called…

rRNA

These molecules are the actual translators, bringing in the amino acid that matches each RNA codon

transfer RNA tRNA

These molecules carry a genetic message that is read three nucleotides (one codon) at a time

mRNA

Within the cell, translation depends on molecules called _____. They can speak the language through a structure at one end called the _____. These bind to the codon of a messenger RNA via the RNA base pairing rules.

tRNA, anticodon

The transfer RNA comes preloaded with the amino acid that matches the RNA sequence in the ____

codon

Genetic code

instructions contained in a gene that tell a cell to make a specific protein

AUG is a _____ codon. UAA, UAG, and UGA are ____ codons

start, stop

A set of three nucleotide long “words” that specify the amino acids for polypeptide chains is the ____ ____.

triplet code

The ribosome exists as two separate components, tRNA binds to mRNA and translation begins. A polypeptide bond grows as a result. This process is called?

initiation

The polypeptide grows longer and tRNA is replaced after every amino acid is created using the ribosome. This process is called?

elongation

Elongation continues until the ribosome reaches a stop codon on the mRNA. The completed polypeptide typically made from several hundreds of amino acids, and the mRNA is released. What is this process called?

termination

Gene regulation

mechanisms that turn on certain genes while keeping other genes turned off in a particular cell

Gene expression

the process whereby genetic information flows from genes to proteins; the flow from the genotype to the phenotype

Why does X chromosome inactivation happen?

it ensures that males (who only have one X chromosome) and females who have two, have the same number of active X genes.

The inactive X in each cell condenses into a compact object called a ____ ____.

barr body

What is a a small RNA molecule that binds to mRNA molecules and prevents them from producing protein called?

microRNAs

Transcription factors

a protein that binds to DNA and functions in initiating or regulating transcription

A series of relay molecules that convey the message from outside of the cell into the cell’s interior cytoplasm and eventually to the nucleus.

signal transduction pathway

This process called _______ involves frequent ____ to ____ signaling that helps the developing organism to properly form the correct organs/body

development, cell, cell

Induction

The mechanism of induction occurs when one group of cells influences the development of an adjacent group of cells.

For example, _______ signals can cause cells to change shape, to migrate, or even to destroy other cells, as in the removal of webbing in the developing ____

inductive, hand

In a developing embryo, ______ genes produce protein signals that turn groups of other genes on and off. They help establish the overall _____ of an organism.

homeotic, structure

Mutagens

physical or chemical factors in the environment that can damage DNA

Carcinogens

cancer-causing agents

Point mutation

the substitution of one DNA nucleotide for another, silent, missense, nonsense

Does not change the amino acid produced, because some amino acids are encoded by more than one RNA sequence, so the protein is unchanged

Cysteine - Cysteine

silent mutation

Substitutes one amino acid for another. This produces a mutant protein, which may be nearly identical or substantially different from the original.

Cysteine - Serine

missense mutation

Changes an amino acid codon to a stop codon. This will produce a shortened protein that is almost always defective.

ACT - UGA - STOP

nonsense mutation

Mutations that add nucleotides (called insertions) or remove nucleotides (called deletions) throw off the reading frame it is called a _____ _____

frameshift mutation