Chapter 11: DNA Molecule of Heredity

nucleotides

DNA consists of subunits called ________

parental

DNA polymerase always moves in the 3' to 5' direction on the ___________ strand

semiconservative replication

DNA replication conserves one parental DNA strand and produces one newly synthesized strand.

polymerase

Daughter DNA strands are synthesized by the enzyme __________

Complementary Base Pair

In nucleic acids, bases that pair by hydrogen bonding. In DNA, adenine is complementary to thymine and guanine is complementary to cytosine; in RNA, adenine is complementary to uracil, and guanine to cytosine.

two

It takes less energy to break apart a A-T base pair because these are held together by ________ hydrogen bonds.

three

It takes more energy to break apart a C-G base pair because these are held together by ______ hydrogen bonds.

complimentary

The bases that can form pairs in DNA are called __________ bases.

DNA Replication

The copying of the double-stranded DNA molecule, producing two identical DNA double helices.

Semiconservative Replication

The process of replication of the DNA double helix; the two DNA strands separate, and each is used as a template for the synthesis of a complementary DNA strand. Consequently, each daughter double helix consists of one parental strand and one new strand.

Double Helix

The shape of the two-stranded DNA molecule; similar to a ladder twisted lengthwise into a corkscrew shape.

sugar

The subunits of DNA are assembled by linking the phosphate of one nucleotide to the __________ of the next.

opposite

The two strands of a DNA double helix are oriented in __________ directions.

double

Thymine (Talley) is a single ring, Oxygen. G-Daddy Guanine is a _________ring, Oxygen. A-T is three. C-G is two.

DNA replication

a process that unwinds parental DNA double helix and produces two identical DNA helices. Base pairing is the foundation of DNA replication.

strand

a single polymer of nucleotides; DNA is composed of two strands would about each other in a double helix; RNA is usually single stranded

DNA polymerase

an enzyme that bonds DNA nucleotides together into a continuous strand, using a preexisting DNA strand as a template

DNA ligase

an enzyme that bonds the terminal sugar in one DNA strand to the terminal phosphate in the second DNA strand, creating a single strand with a continuous sugar-phosphate backbone

DNA helicase

an enzyme that helps unwind the DNA double helix during DNA replication

bacteriophages

certain viruses that infect only bacteria are called this--meaning "bacteria eaters"--this "phage" depends on a host bacterium for every aspect of its life cycle.

DNA polymerases

enzymes that move along each separated parental DNA strand, matching bases on the parental strands with complementary free nucleotides.

DNA helicases

enzymes that pull apart the parental DNA double helix, so that the bases of the two DNA strands no longer form base pair with one another.

DNA ligase

enzymes that stitch the fragments of DNA until each daughter strand consists of one long, continuous DNA polymer.

Complementary base pair

in nucleic acids, bases that pair by hydrogen bonding. In DNA, adenine is complementary to thymine and guanine is complementary to cytosine; in RNA adenine is complementary to uracil and guanine to cytosine

nucleotides

long chains made of subunits that make up DNA--consists of three parts: a phoshphate group, a sugar molecule and one of four nitrogen bases.

mutations

occasional changes in the nucleotide sequence do occur that can be often harmful or damaging--or can have no effect--or can, in very rare instances, be beneficial.

inversion

occurs when a piece of DNA is cut out of chromosome, turned around, and reinserted into the gap.

insertion mutation

occurs when one or more nucleotide pairs are inserted into the DNA double helix.

deletion mutation

occurs when one or more nucleotides pairs are removed from the double helix.

base

one of the nitrogen-containing, single or double ringed structures that distinguishes one nucleotide from another. In DNA, the bases are adenine, guanine, cytosine, and thymine

free nucleotides

previously synthesized nucleotides in the cytoplasm that are imported into the nucleus and with a variety of enzymes that unwind the parental DNA double helix and synthesize new DNA strands.

translocation

results when a chunk of DNA, often very large, is removed from one chromosome and attached to a different one. *Figure 11-9b*

point mutations

same as nucleotide substitution--when invdividual nucleotides in the DNA sequence are changed--sometimes enzymes replace the parental nucleotide instead of the mismatched one, the result base pair is complementary, but incorrect.

DNA replication

the copying of the double-stranded DNA molecule, producing two identical DNA double helices

sugar-phosphate backbone

the phosphate group of one nucleotide is bonded to the sugar of the next nucleotide in a DNA strand, thus producing a backbone of alternating, covalently bonded sugars and phosphates.

semiconservative replication

the process of replication of DNA double helix; the two DNA strands separate, and each is used as a template for the synthesis of complementary DNA strand. consequent, each daughter double helix consists of one parental strand and one new strand

Double helix

the shape of the two-stranded DNA molecule; similar to a ladder twisted lengthwise into a corkscrew shape

bases

there are four nitrogen bases that make up nucleotides in DNA--adenine (A)--thymine (T)--guanine (G)--cytosine (C).

double helix

two strands of DNA that are wound about each other to form this shape--like a spiral staircase.

nucleotide substitutions

when invdividual nucleotides in the DNA sequence are changed--sometimes enzymes replace the parental nucleotide instead of the mismatched one, the result base pair is complementary, but incorrect. Also called point mutations.

adenine

(A)--a purine base found in DNA and RNA

cytosine

(C)--A pyrimidine base found in DNA.

guanine

(G)--a purine base found in DNA and RNA

thymine

(T)--A pyrimidine base found in DNA.

Sugar-Phosphate Backbone

A chain of sugars and phosphates in DNA and RNA; the sugar of one nucleotide bonds to the phosphate of the next nucleotide in a DNA or RNA strand. The bases in DNA or RNA are attached to the sugars of the backbone.

Mutation

A change in the base sequence of DNA in a gene; normally refers to a genetic change significant enough to alter the appearance or function of the organism.

Deoxyribonucleic Acid (DNA)

A molecule composed of deoxyribose nucleotides; contains the genetic information of all living cells.

Nucleotide Substitution

A mutation in which a single base pair in DNA has been changed.

Point Mutations

A mutation in which a single base pair in DNA has been changed.

Insertion Mutation

A mutation in which one or more pairs of nucleotides are inserted into a gene.

Deletion Mutation

A mutation in which one or more pairs of nucleotides are removed from a gene.

Inversion

A mutation that occurs when a piece of DNA is cut out of a chromosome, turned around, and reinserted into the gap.

Translocation

A mutation that occurs when a piece of DNA is removed from one chromosome and attached to another chromosome.

Adenine (A)

A nitrogenous base found in both DNA and RNA; abbreviated as A.

Cytosine (C)

A nitrogenous base found in both DNA and RNA; abbreviated as C.

Guanine (G)

A nitrogenous base found in both DNA and RNA; abbreviated as G.

Thymine (T)

A nitrogenous base found only in DNA; abbreviated as T.

Strand

A single polymer of nucleotides; DNA is composed of two strands wound about each other in a double helix; RNA is usually single stranded.

Nucleotide

A subunit of which nucleic acids are composed; a phosphate group bonded to a sugar (deoxyribose in DNA), which is in turn bonded to a nitrogen-containing base (adenine, guanine, cytosine, or thymine in DNA).

Bacteriophage

A virus specialized to attack bacteria.

complementary base pairs

All of the bases of the two strands of DNA double helix are complementary to each other--Adenine forms hydrogen bonds with only thymine and guanine forms hydrogen bonds with cytosine.

DNA Polymerases

An enzyme that bonds DNA nucleotides together into a continuous strand, using a preexisting DNA strand as a template.

DNA Ligase

An enzyme that bonds the terminal sugar in one DNA strand to the terminal phosphate in a second DNA strand, creating a single strand with a continuous sugar-phosphate backbone.

DNA Helicase

An enzyme that helps unwind the DNA double helix during DNA replication.

double helix

As it is found in chromosomes, two DNA polymers are wound together into a structure called a _______ _________

thymine

a nitrogenous base found in both DNA and RNA; abbreviated as T

DNA strand

a polymer consisting of many nucleotide subunits.

cytosine

a nitrogenous base found in both DNA and RNA; abbreviated as C

guanine

a nitrogenous base found in both DNA and RNA; abbreviated as G

phosphate group, dioxyribose, base

Each subunit has three parts

ligase

In eukaryotic cells, the daughter DNA strands are synthesized in pieces these pieces are joined by the enzyme _________

Free Nucleotides

Nucleotides that have not been joined together to form a DNA or RNA strand.

Base

One of the nitrogen-containing, single- or double-ringed structures that distinguishes one nucleotide from another. In DNA, the bases are adenine, guanine, cytosine, and thymine.

mutations

Sometimes, mistakes are made during DNA replication. If uncorrected, these mistakes are called ________

away

The 5' direction on one strand leads toward the replication fork and the 5' strand leads ________ from the fork.

helicase

The DNA double helix is unwound by an enzyme called ______

semiconservative

When DNA is replicated, two new DNA double helices are formed each consisting of one parental strand and one new daughter strand. For this reason, DNA replication is called ______________.

nucleotide substitution, point mutation

When a single nucleotide is changed, this is called __________.

sugar phosphate backbone

a chain of sugars and phosphates in DNA and RNA; the sugar of one nucleotide bonds to the phosphate of the next nucleotide in a DNA or RNA stand. The bases in DNA or RNA are attached to the sugars of the backbone

mutation

a change in base sequence of DNA in a gene; often used to refer to a genetic change that is significant enough to alter the appearance or function of the organism

Nucleotide

a molecule with a three-part structure: a five carbon sugar, a phosphate functional group, and a nitrogen containing base that differs among nucleotides

point mutation

a mutation in which a single base pair in DNA has been changed

insertion mutation

a mutation in which one or more pairs of nucleotides are inserted into a into a gene

deletion mutation

a mutation in which one or more pairs of nucleotides are removed from a gene

inversion

a mutation that occurs when a piece of DNA is cut out of a chromosome, turned around, and reinserted into the gap

translocation

a mutation that occurs when a piece of DNA is removed from one chromosome and attached to another chromosome

adenine

a nitrogenous base found in both DNA and RNA; abbreviated as A