BIO 160 Chapter 10

Question 1

Chemical compositions DNA vs RNA

Answer 1

DNA RNA
Stands for: DeoxyriboNucleicAcid RiboNucleicAcid
Definition: A nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms. RNA, single-stranded chain of alternating phosphate and ribose units with the bases adenine, guanine, cytosine, and uracil bonded to the ribose. RNA molecules are involved in protein synthesis and sometimes in the transmission of genetic information.
Job/Role: Medium of long-term storage and transmission of genetic information The main job of RNA is to transfer the genetic code need for the creation of proteins from the nucleus to the ribosome. this process prevents the DNA from having to leave the nucleus, so it stays safe. Without RNA, proteins could never be made.
Unique Features: The helix geometry of DNA is of B-Form. DNA is completely protected by the body i.e. the body destroys enzymes that cleave DNA. DNA can be damaged by exposure to Ultra-violet rays The helix geometry of RNA is of A-Form. RNA strands are continually made, broken down and reused. RNA is more resistant to damage by Ultra-violet rays.
Predominant Structure: Typically a double- stranded molecule with a long chain of nucleotides A single-stranded molecule in most of its biological roles and has a shorter chain of nucleotides
Bases & Sugars: DNA is a long polymer with a deoxyribose and phosphate backbone and four different bases: adenine, guanine, cytosine and thymine RNA is a polymer with a ribose and phosphate backbone and four different bases: adenine, guanine, cytosine, and uracil
Pairing of Bases: A-T(Adenine-Thymine), G-C(Guanine-Cytosine) A-U(Adenine-Uracil), G-C(Guanine-Cytosine)
Stability: Deoxyribose sugar in DNA is less reactive because of C-H bonds. Stable in alkaline conditions. DNA has smaller grooves where the damaging enzyme can attach which makes it harder for the enzyme to attack DNA. Ribose sugar is more reactive because of C-OH (hydroxyl) bonds. Not stable in alkaline conditions. RNA on the other hand has larger grooves which makes it easier to be attacked by enzymes.

Question 2

Describe the key features of the overall shape of a DNA molecule

Answer 2

double helix, sugar phosphate backbone.. base pairs inside..

Question 3

Explain how the structure of DNA was determined

Answer 3

Crick was studying protein structure using x-ray crystallography. saw a x-ray image, saw basic shape was a helix the thickness of helix suggested two polynucleotides.. put backbones on the outside

Question 4

What is the polarity of DNA?

Answer 4

negative

Question 5

molecular bology

Answer 5

study of heredity at the molecular level

Question 6

nucleotides

Answer 6

long chains of chemical units

Question 7

full name of DNA

Answer 7

deoxyribonucleic acid

Question 8

deoxyribose

Answer 8

sugar missing an oxygen

Question 9

single ring structures

Answer 9

Cytosine and Thymine

Question 10

double ring structures

Answer 10

Adenine and Guanine

Question 11

Uracil

Answer 11

replaces Thymine in RNA

Question 12

ribose

Answer 12

sugar in RNA

Question 13

polynucleotide strands

Answer 13

double helix

Question 14

DNA polymerases

Answer 14

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

Question 15

molecular chain of command

Answer 15

DNA=>RNA=> protein synthesis

Question 16

transcription

Answer 16

transfer of genetic information from DNA to RNA

Question 17

translation

Answer 17

translation from RNA to protein

Question 18

why is one gene one enzyme not correct?

Answer 18

keratin is a product of a gene, many proteins have two or more different polypeptide chains.. each plypeptide is specified by its own gene

Question 19

codons

Answer 19

three-base words

Question 20

genetic code

Answer 20

the set of rule that convert a nucleotide sequence in RNA to an amino acid sequence

Question 21

AUG

Answer 21

start of a polypeptide chain and Methionine

Question 22

stop codons

Answer 22

UAA UGA UAG

Question 23

promoter

Answer 23

start transcribing signal

Question 24

RNA Elongation

Answer 24

2nd phase of transcription, RNA grows longer

Question 25

terminatior

Answer 25

end of the gene, 3rd phase of transcription

Question 26

mRNA

Answer 26

messenger RNA, the molecule that is translated into protein

Question 27

cap and tail

Answer 27

protect the RNA from attace by cellular enzymes and help ribosomes recognize the RNA as mRNA

Question 28

introns

Answer 28

noncoding regions

Question 29

exons

Answer 29

the coding regions - theparts of a gene that are expressed

Question 30

RNA splicing

Answer 30

introns are removed and exons are joined

Question 31

Translation players

Answer 31

mRNA, tRNA and Ribosomes

Question 32

tRNA

Answer 32

transfer RNA, the molecular interpreter.. pick up appropriate amino acids, and recognize the appropriate codons

Question 33

anticodon

Answer 33

on tRNA like the codon triplet on mRNA

Question 34

ribosomes

Answer 34

organelles that coordinate the functioning fo fthe mRNA and tRNA and actually make polypeptides

Question 35

Translation Process

Answer 35

initiation, Elongation, Termination

Question 36

Initiation

Answer 36

mRNA molecuel binds to a small ribosomal subunit.. tRNA binds to the start codon the initiator tRNA carries the amino acid methionine, anticodon A large ribosomal subunit binds to the small one, creating a functional ribosome

Question 37

Elongation

Answer 37

amino acids are added one by one to the first amino acid, 1. Codon Recognition 2. Peptide bond formation 3 Translocation

Question 38

mutation

Answer 38

any change in the nucleotide sequence of DNA

Question 39

virus

Answer 39

genes in a box

Question 40

bacteriophages

Answer 40

viruses that attack bacteria, bacteria eaters

Question 41

lytic cycle

Answer 41

after many copies of the phages are produced within the bacterial cell, the bacteria breaks open

Question 42

lysogenic cycle

Answer 42

viral DNA replication occurs without phage production or the death of the cell, many cell divisions.. prophage

Question 43

HIV

Answer 43

RNA virus with special twists

Question 44

retrovirus

Answer 44

RNA virus that reproduces by means of a DNA molecule

Question 45

reverse transcriptase

Answer 45

catalyzes reverse transcripton:Synthesis of DNA on an RNA template

Question 46

provirus

Answer 46

Viral DNA inserted into Chromosomal DNA

Question 47

viroids

Answer 47

small circular RNA molecules that infect plants

Question 48

prions

Answer 48

infectious protiens that cause brain diseases in animals