Lecture 2: Cells and DNa

Question 1

What are the three pieces of Darwin’s postulates?

Answer 1

1. Individuals compete to survive
2. Individuals within a population vary
3. Some of these variations are heritable

Question 2

What is the problem with Darwin’s view of inheritance?

Answer 2

Blending inheritance from parents eventually averages out, dilutes and eliminates variation.

Question 3

When did Crick and Watson discover DNA structure?

Answer 3

April 1953

Question 4

What three things can DNA do?

Answer 4

1. Coding for primary structure of protein.
2. Coding for regulatory sequences
3. Specifies the structure of some RNA

Question 5

What is a codon?

Answer 5

DNA grouped in triplet base pairs.

Question 6

How many different codons and amino acids do humans have?

Answer 6

Codon: 64

amino acids: 20

Question 7

When a base pair is different within a codon but results in the same amino acid, what is this change called?

Answer 7

synonymous substitution.

Question 8

Why does regulatory sequences cause phenotypic variation?

Answer 8

Because they usually consists of binding sits that either activate or repress proteins.

Question 9

Define gene.

Answer 9

Segment of DNA that makes a functional product and segregates as a unit during gamete formation.

Question 10

What is the point where a gene found on a chromosome is called?

Answer 10

Locus.

Question 11

What are two important genetic types of variation?

Answer 11

Mutation and recombination.

Question 12

What are Mendel’s laws?

Answer 12

Law of Segregation:
Alternative versions of alleles account for variation, an organism inherits two alleles, one from each parent.
Law of Independent Assortment:
One traits does affect another, each particle has equal probability to be transmitted.

Question 13

Define genotype and phenotype:

Answer 13

Genotype: Combination of alleles an organism carries
Phenotype: physical characteristics expressed by an individual.

Question 14

How does distance between genes play a role in crossing over?

Answer 14

The farther they are, the more likely for their to be crossing over.

Question 15

What is the genetic definition of evolution?

Answer 15

Changes in gene frequency in populations across generations.

Question 16

What does modern synthesis conclude using both mendelian and Darwinian theory?

Answer 16

Traits are determined by multiple alleles, resulting in a continuous variation.

Question 17

Describe how sexual reproduction, natural selection and mutation influence variation.

Answer 17

Sexual reproduction maintains consistent variation.
Natural selection decreases variation.
Mutation increases variation.

Question 18

What are the three broad evolutionary constraints?

Answer 18

Historical, developmental/genetic, material.

Question 19

What are aspects of historical constraint?

Answer 19

Genetic drift, disequilibrium, local and global optimal adaptations.

Question 20

What is pleiotropy?

Answer 20

Genes that affect many aspects of a phenotype.

Question 21

What are some material constraints?

Answer 21

Gravity, volume to surface area ratio, fluid dynamics.