Molecular Genetics

Question 1

How many nitrogenous bases are there?

Answer 1

4

Question 2

What is the backbone made out of in DNA?

Answer 2

Phosphate and Sugar

it repeats

Question 3

Bases are bonded to..

Answer 3

sugars, not directly the phosphate.

Question 4

The sugar in DNA is..

Answer 4

deoxyribose = 5 carbon sugar (pentose sugar)

Question 5

Chargaff’s Rule

Answer 5

amount of A = T
amount of C = G

Question 6

Nucleotides

Answer 6

sugar, phosphate, and one base

Question 7

Purines and Pyrimidines

Answer 7

Purines - A and G = 2 rings
Pyrimidines - C and T = 1 ring

Question 8

Double Helix

Answer 8

• the shape of dna
• two strands parallel to each other

Question 9

Types of bonds in DNA

Answer 9

Hydrogen bonds between bases
Covalent bonds between sugar and phosphate

G and C are triple hydrogen bonded, A ant T are double hydrogen bonded

Question 10

The enzymes involved in DNA replication

Answer 10

DNA helicase - seperates the two stands
DNA polymerase - adds new nucleotides to the unzipped original DNA molecule
DNA ligase - seals the new nucleotides into place.

Question 11

DNA is replicated in a..

Answer 11

semi-conservative matter
which means that each new DNA molecule has one orginal and new strand

DNA replcation occurs in the nucleus.

Question 12

DNA vs RNA

Answer 12

• RNA has ribose sugar instead of deoxyribose
• RNA has uracil instead of thymine
• RNA is a single stranded structure.

Question 13

Types of RNA

Answer 13

mRNA - carries the coding sequence for protein synthesis
tRNA - molecules carries the anticodons to the ribosomes and decodes the mRNA into a protein
rRNA - makes up the structure of ribosomes. made in the nucleolus but shipped to the cytoplasm.

Question 14

Transcription

Answer 14

occurs in the nucleus of eukaryotes and cytoplasm of prokaryotes
one of the DNA strands is used as a template to make RNA.

Question 15

RNA Polymerase

Answer 15

binds to DNA and seperates the two stands, and one of the strands is used as a template for making RNA.

Question 16

Promoter and Terminiation Site

Answer 16

• a region of DNA where the RNA polymerase attaches and where it starts transcription.
• a region of DNA where the RNA polymerase detattaches and where transcription ends.

Question 17

Translation - what do ribosomes do?

Answer 17

the site of where protein synthesis takes place

Question 18

Codons vs Anticodons

Answer 18

codons - a sequnce of three nucleotides in mRNA that determines the position of amino acids.
anti-codons - a sequence of three nucleotides in tRNA that have an opposite sequence that matches specific codons, they binds to mRNA and designate that amino acid.

Question 19

Genetic Code

Answer 19

the instructions in a gene that tell a cell how to make a specific protein

Question 20

Start and Stop codons

Answer 20

• there are specific codons that start the translation process
  (AUG)
• there are specific codons that end the translation process
  (UAG, UGA, UAA)

Question 21

Importance of redundant genetic code

Answer 21

• minimizes the harmful effects that incorrectly placed nucleotides have on protein synthesis
  (because the third letter can be changed without changing the amino acid.)

Question 22

Why is the genetic code 3 bases per codon?

Answer 22

we need 20 amino acids but 4^2 is only 16, but 14^3 is 64 which is why we have wobble letters.

Question 23

Code is..

Answer 23

Universal, DNA of different species can be combined together.

Question 24

Chromosomal Mutations involve…

Answer 24

more than one gene

Question 25

Chromosomal Mutations | may invole change in structure or loss of part of structure.

Answer 25

deletion - a piece of chromosome is lost inversion - a piece of chromosme break off and flips around backward, the segment then reattaches. translocation - involves two chromosomes that aren't homologous, part of one chromosome is transferred to the other. duplication - gene sequence is repeated nondisjuction - failure of chromosomes to seperate during mitosis, may cause too many or too few chromosomes.

Question 26

Gene Mutations involve..

Answer 26

one gene! | change in the nucleotide sequence of a gene

Question 26

Point Mutations

Answer 26

- change of a single nucleotide - includes the deletion, insertion, or substitution of ONE nucleotide in a gene - results in frameshift mutation which changes the rest of the nucleotides are the change in the single nucleotides.

Question 26

Silent, Nonsense, and Missense Mutations

Answer 26

silent - substituting a base does NOT change the amino acid nonsense - substituation leads to a STOP codon missense - substitution leads to a change in amino acid

Question 26

What mutations can be passed to offspring?

Answer 26

mutations in the gametes/sperm cells (least common) mutations in the somatic cells cannot be passed to offspring (most common)