1 | (Lenhard) Essentials of Genetics

Question 1

Genetic analysis requires ________ _________.

Answer 1

genetic variation

Question 2

DNA has a _____ _______ backbone.

Answer 2

sugar phosphate

Question 3

Phosphates have _________ charges.

Answer 3

negative

Question 4

The interior of a DNA helix is __________.

Answer 4

hydrophobic

Question 5

Two nucleotides on single strands are linked by _______ _______.

Answer 5

hydrogen bonds

Question 6

What are conservative, semiconservative, dispersive replication?

Answer 6

Semiconservative replication derives its name from the fact that this mechanism of transcription was one of three models originally proposed for DNA replication:

• Semiconservative replication would produce two copies that each contained one of the original strands of DNA and one new strand. Semiconservative replication is beneficial to DNA repair. During replication, the new strand of DNA adjusts to the modifications made on the template strand.
• Conservative replication would leave the two original template DNA strands together in a double helix and would produce a copy composed of two new strands containing all of the new DNA base pairs.
• Dispersive replication would produce two copies of the DNA, both containing distinct regions of DNA composed of either both original strands or both new strands. The strands of DNA were originally thought to be broken at every tenth base pair to add the new DNA template. Eventually, all new DNA would make up the double helix after many generations of replication.

Question 7

DNA replication is ______________. (conservative, semiconservative, dispersive)

Answer 7

Semiconservative

Question 8

The genetic code is _______.
Explain what this means

Answer 8

redundant

Although each codon is specific for only one amino acid (or one stop signal), the genetic code is described as degenerate, or redundant, because a single amino acid may be coded for by more than one codon.

Question 9

Central dogma

Answer 9

Information cannot be transferred from protein to protein or protein to nucleic acid, but can be transferred between nucleic acids and from
nucleic acid to protein.

–> The translation of RNA into protein is unidirectional.

Question 10

Mutations Change the ________ of DNA

Answer 10

sequence

Question 11

Mutation - what a transition (transversion)?
What subtypes?

Answer 11

a nucleotide replaced by another

• synonymous
• missense (conservative)
• missense (nonconservative)
• nonsense

Question 12

Mutation - explain different transitions: synonymous, missense, nonsense

Answer 12

• synonymous: altered codon gives same AA
• missense (conservative): altered codon gives chemically similar AA
• missense (nonconservative): altered codon gives chemically dissimilar AA
• nonsense - altered codon gives chain termination

Question 13

What type of mutations apart from transition?

Answer 13

indels

Question 14

What types of indel?

What do they cause?

Answer 14

Base insertion
Base deletion

–> a whole new set of AAs, unless inserted/deleted nucleotide number is a multiple of 3

Question 15

A Locus Can Have Many Different ________ Alleles

or

A Locus Can Have More Than One ________ Allele

Answer 15

mutant

wild-type

Question 16

A Locus Can Have More Than One Wild-Type Allele

name for this?

example?

Answer 16

polymorphic distribution of alleles –> no individual allele that can be considered to be the sole wild type

eg ABO human blood group locus (encodes a galactosyltransferase whose specificity determines the blood group.)

Question 17

Most eukaryotic organisms (higher
plants and animals) are ________.

Answer 17

diploid

diploid cell: pairs of homologous chromosomes
(one from each parent)

Question 18

Mitosis vs Meiosis ?

Answer 18

There are two kinds of cell division: mitosis and meiosis. What’s the Difference?

Mitosis produces two genetically identical “daughter” cells from a single “parent” cell

Meiosis produces cells that are genetically unique from the parent and contain only half as much DNA

Question 19

Mitosi