DNA (U3)

Question 1

Nucleic Acids

Answer 1

2 types - DNA and RNA (Both polymers of nucleotides)

Question 2

DNA Structure

Answer 2

Double Helix made up of repeating nucleotide units

Question 3

Nucleotides

Answer 3

Made up of 3 main parts

Phosphate (phosphoric Acid); 5 carbon sugars (deoxyribosome); One of four nitrogen bases

Question 4

4 nitrogen bases

Answer 4

Adenine and Guanine (Two-carbon ring bases; purines) Thymine and Cytosine (One-carbon ring bases; pyrimidines)
A+T and G+C

Question 5

DNA Replication

Answer 5

• Untwisted by enzymes (helicase) breaking the bonds
  -New complementary nucleotides pair with complementary bases on the exposed strand (ligase glues sugar-phosphate backbone together)
  -Winds back up into helix shape
  (Called semiconservative)

Question 6

DNA functions

Answer 6

Replicates itself (each new cell as identical copy)
Controls activities by producing proteins
Undergo occasional mutations

Question 7

recombinant DNA

Answer 7

DNA genes from 2 different organisms

Question 8

Uses for recombinant DNA

Answer 8

• generate DNA library
• Identify Specific genes
• Produce synthetic copies of genes to mass produce chemicals like insulin
• Insert genetic material into chromosomes that will regulate functions

Question 9

RNA

Answer 9

Sugar = Ribose; Bases = AUCG; Single-Stranded; protein synthesis; Found in nucleus and cytoplasm

Question 10

Protein Synthesis

Answer 10

Uses DNA to create protein - DNA contains instructions to create proteins; Proteins affect our characteristics
Protein is created in cytoplasm from mRNA strand

Question 11

Transcription

Answer 11

process of making mRNA from DNA template
Hydrogen bonds between base pairs are broken to provide DNA template (Polymerase)
free-floating nucleotides join selected genes on DNA template (polymerase assist)
(Ligase) glues sugar-phosphate backbone back together; enzymes break the new hydrogen bonds, RNA strand formed

Question 12

Translation

Answer 12

process to go from mRNA to protein
Initation - mRNA associated with ribosome in cytoplasm; larger subunit attaches to mRNA; first tRNA arrives with anticodon and binds to complimentary mRNA forming functional complex
Elongation - second tRNA peptide bonds with second codon; ribosome moves down mRNA by 1 codon; third tRNA bonds with 3rd codon…
Termination - Elongation continues until termination (stop) codon reached; finished protein released; mRNA read by more ribosomes or disenigrates

Question 13

Codons

Answer 13

every 3 bases in DNA strand code for 1 amino Acid; once code is transcribed each set of three on mRNA is called a codon (64 possible combinations)
AUG = start codon; UUA and UAG = stop codon
at very end always a adenine tail to show mRNA is still functional, falls off after used

Question 14

Gene Mutation

Answer 14

permanent aleration in DNA sequence
Hereditary Mutations/Germline mutations - in gametes
Aquired/Somatic mutations - occur as sometime in persons life, only in certain cells - body cells

Question 15

Chromosomal mutations

Answer 15

Deletion - Peices breaks off (lost); Duplication; Inversion - piece breaks off and reattches reversed; Translocation - piece breaks off attaches to nonhomologous chromosomes; Nondisjunction - pair of chromosomes fail to separate during cell division; Point Mutations - change in single nitrogen base; Frame shift mutation - addition/deletion of nitrogen base

Question 16

Environmental Mutagens

Answer 16

Chemical (drugs, fertilizers, food additives) and Radiation

Question 17

Examples

Answer 17

Cancer (somatic mutation); Down Syndrome (chromosomal translocation); Sickle Cell Anemia; Hemophelia (germ cell mutation

Question 18

Metabolism

Answer 18

Refers to all chemical reactions of a cell

Question 19

Enzymes; Apoenzyme; Coenzyme

Answer 19

A protein Catalyst (speeds up certain reactions)
(protein portion)
(non-protein portion)
Speeds up reactions by lowering activation energy

Question 20

Substrate; Activation energy

Answer 20

reactant enzyme acts on

many reactions won’t occur unless energy is added to start reaction off

Question 21

Thyroxin; Thyrogolbulin

Answer 21

-Protein hormone secreted into blood stream by thyroid cells
Stimulate most cells to metabolize faster
-storage form of thyroxin

Question 22

Simple goiter; exothalmic goiter

Answer 22

• thyroid gland unable to meet demands of body; enlarges to compensate
• Graves disease - excessive production of thyroid hormome

Question 23

Lock and Key theory

Answer 23

Reactants must be brought close together; bond to active site on enzyme (enzyme sometimes changes shape for reactants); reaction occurs and products are released (enzyme goes back to tertiary shape
(enzyme acts like key unlocking substrate activity)

Question 24

Metabolic Pathway

Answer 24

Begining subtrate - intermediate products/reactants - final product
1 enzyme 2 enzymes 3 enzymes

Question 25

Factors Affecting Enzyme Activity

Answer 25

HEAVY METALS - Bond with parts of enzyme changing their shape (noncompetitive inhibition); COMPETITIVE INHIBITION - molecules shaped like substrate competing with them; TEMPERATURE - Cold temperature slows down enzymatic reactions (high temps cause them to stop); PH - operates best at preferred ph level; SUBSTRATE CONCENTRATION - there greater the concentration, the greater the rate of reaction; ENZYME CONCENTRATION - more enzyme, greater rate of reaction