Biology 100- Chapter 10

Front 1

DNA

Back 1

deoxyribonucleic acid

determines basic characteristics of whether an organism will have scales, make feathers, produce leaves or grow into a mushroom

Front 2

DNA genetic code

Back 2

is a universal code

Front 3

gene

Back 3

a segment of DNA, genes make a copy of themselves and also express their coded message by making a strand of RNA

Front 4

All nucleic acids are composed of

Back 4

a sugar based backbone with 4 nitrogenous bases bonded to the backbone

Adenine, guanine and cytosine

DNA is composed of thymine

RNA is single

Front 5

Bonds

Back 5

Adenine bonds with thymine

guanine bonds with cytosine

In RNA Uracil is substituted for thymine and binds with adenine

Front 6

Replication

Back 6

process that copies DNA molecules

Front 7

transcription

Back 7

occurs in the nucleus and results in a final product called mRNA. During this a small section of DNA unfolds and a different enzyme called RNA polymerase binds to the DNA.

Front 8

translation

Back 8

is the 2nd part of the process, occus in cytoplasm, where messenger RNA and tRNA come into play

Front 9

condons

Back 9

series of 3 mRNA nucleotides

Example: UUCGAU contains 2 condons

1st is UUC 2nd is GAU

Front 10

anticondon

Back 10

mRNA contains dozens to thousands of condons, tRNA contains one anticondon

complimentary strand that exists on the tRNA molecules

Front 11

UUCGAU example

Back 11

UUC would match up to AAG anticondon and the GAU would match up to CUA

Front 12

operons

Back 12

controlled in prokaryotes to turn on or off

Front 13

nucleotide

Back 13

are building blocks of nucleic acid. an organic monomer consisting of a 5 carbon sugar covalently bonded to a nitrogenous base and a phosphate group

Front 14

polynucleotide

Back 14

tend to be very long and can have a sequence of nucleotides so a large number of polynucleotide chains are possible

Front 15

sugar phosphate backbone

Back 15

repeating pattern of a sugar phosphate sugar phosphate

Front 16

Nucleotide has 3 components

Back 16

The phosphate group as its center, is the source of acid in nucleic acid.

The sugar has five carbon atoms (deoxyribose)-missing oxygen atom

Nitrogenous base are basic

Front 17

double helix

Back 17

made up of 2 polynuclieotide strands

Front 18

DNA polymerases

Back 18

enzymes that make the covalent bonds between the nucleotides of a new DNA strand

Front 19

DNA replication begins

Back 19

at specific sites on a double helix, called origins of replication

Front 20

2 main stages of protein snythesis

Back 20

transcription- transfer of genetic information from DNA to RNA molecule

and translation- transfer from RNA into a protein

Front 21

Condons

Back 21

genetic instructions for the amino acid sequence of a polypeptide chain written in DNA and RNA as a series of three based words

Front 22

genetic code

Back 22

set of rules relating nucleotide sequence to amino acid sequence

Front 23

The triplet AUG provides dual function

Back 23

codes for amino acids methinonine and provides signal for the start of a polypeptide chain

Front 24

Promoter

Back 24

"start transcribing" signal, located in the DNA at the beginning of the gene, is the site where an enyzme RNA polymerase attaches and initates transcription

Front 25

transcription 1st phase

Back 25

1st phase is initiation, the attachment of RNA polymerase to the promoter and the start of RNA synthesis

Front 26

transcription 2nd phase

Back 26

RNA elongation:, RNA grows longer. peels away from DNA template, allowing 2 separated DNA strands to come back together

Front 27

transcription 3rd phase

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Termination: the RNA polymerase reaches a special sequence of bases in the DNA template called the terminator. This sequence signals th end of the gene

Front 28

messenger mRNA

Back 28

first important ingredient required for translation is the mRNA produced by transcription. Requires enzymes and sources of chemical energy such as ATP

Front 29

introns

Back 29

internal noncoding regions

Front 30

exons

Back 30

the coding regions, parts of a gene that are expressed

Front 31

RNA splicing

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exons are joined to produce an mRNA molecule with a continuous coding sequence- this is believed to play role in allowing humans to produce many thousands more polypeptides

Front 32

anticondon

Back 32

complementary to a condon triplet on mRNA. During translation the anticondon on the tRNA recognizes a particular condon on the mRNA by using base pairing rules

Front 33

ribosomes

Back 33

organelles that coordinate the functioning of the mRNA and tRNA and actually make polypeptides

Front 34

translation 1st phase

Back 34

initiation: brings together the mRNA, the first amino acid with its attached tRNA and the two subunits of a ribosome. Occurs in two steps

1. an mRNA molecule binds to a small ribosome subunit, a special initator tRNA then binds to the start codon

2. a large ribosomal unit binds to the small one creating a functional ribosome

Front 35

translation 2nd phase

Back 35

Elongation: 3 step process

1. condon recongition, peptide bond formation, translocation

Front 36

translation 3rd phase

Back 36

termination: elongation happens until stop condon reaches ribosomes A site.

Front 37

sequence of DNA

Back 37

DNA-RNA-Protein

Front 38

mutation

Back 38

change in nucleotide sequence in DNA

Types of mutations: silent and missense, nonsense

Front 39

mutagens

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sources of mutation are physical and chemical agents, some act as carcinogens, agents that cause cancer. Most common physical mutagen is high energy radiation

Front 40

virus

Back 40

genes in a box- survives by infecting a living cell with genetic material that directs the cell's molecular machinery to make more viruses.

Front 41

bacteriophages

Back 41

viruses that can attack bacteria

Front 42

lytic cycle

Back 42

once the virus infect bacterium, it enters a reproductive cycle

Front 43

lysogenic cycle

Back 43

viral DNA replication occurs without phage production or the death of the cell

Front 44

retrovirus

Back 44

an RNA virus that reproduces by means of a DNA molecule

Front 45

provirus

Back 45

viral DNA that inserts into a host genome

Front 46

cellular differentiation

Back 46

cells must become specialized in stucture and function

Front 47

gene regulation

Back 47

turning off and on of genes that leads to specialization

Front 48

gene expression

Back 48

overall process by which genetic information flows from genes to proteins

from genotype to phenotype

Front 49

operon

Back 49

a cluster of genes with related functions along with the controlled sequences-acts as a switch that is turned off and on depending on whether specific protein is bound there

Front 50

transcription factors

Back 50

bind to DNA or to other proteins that bind to DNA, a protein that functions by initating or regulating transcription

Front 51

oncogene

Back 51

gene that causes cancer

Front 52

proto-oncogene

Back 52

a normal gene that has potential to become a oncogene. For a proto-oncogene to become an oncogene a mutation must occur in the cell's DNA

Front 53

recombinant DNA

Back 53

results when scientists combine nucleotide sequences from two different sources, often from different species to form single DNA molecule