Exam 2

Question 1

chromosomes

Answer 1

structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes

Question 2

genes/genetics

Answer 2

Gene- a piece of DNA that codes for a product (usually a protein)
Genetics- the study of life

Question 3

alleles/dominant and recessive

Answer 3

variant of a gene

- Dominant alleles only need one copy present, recessive alleles need two copies of the allele

Question 4

mitosis

Answer 4

a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus

Question 5

meiosis

Answer 5

a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores.

Question 6

random alignment

Answer 6

chromosomes during metaphase I allows equal opportunity for a particular chromosome to migrate into a cell. This type of independent assortment gives rise to exponential gene combinations in the offspring

Question 7

crossing-over

Answer 7

the exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring

Question 8

x and y chromosomes

Answer 8

x= female
y= male

Question 9

co-dominance of ABO blood groups

Answer 9

possibility for the above couple to have a baby with type A blood? 50%
possibility for the couple to have a baby with type O blood? 0%
Use the ABO alleles for blood type to demonstrate the following genotypes:
-heterozygous: AB or AO or BO
-homozygous dominant: AA or BB
-homozygous recessive: OO
-co-dominant: AB

Question 10

mutations

Answer 10

errors in copying genes/chromosomes

Question 11

pleiotropic traits

Answer 11

gene has multiple effects on phenotype (i.e. testosterone )

Question 12

polygenic traits

Answer 12

determined by effects of two or more genes (i.e. eye color and height)

Question 13

detrimental alleles

Answer 13

An allele that results in a lower fitness than an allele which instead is designated as neutral or beneficial.

Question 14

sex-linked traits

Answer 14

a gene is found only on the X chromosome and not the Y chromosome, it is said to be a sex-linked trait. Because the gene controlling the trait is located on the sex chromosome, sex linkage is linked to the gender of the individual

Question 15

hemophilia

Answer 15

•	Hemophilia A – 
-	Sex linked on X chromosome
-	Most common in males (1 in 10,000 in males 1 in 100,000,000 for females)
•	Hemophilia B – 
-	Sex linked on X chromosome
-	Most common in males (same stats as A)
•	Hemophilia C –
-	Non sex linked
-	Occurs in males and females

Question 16

heterozygous carrier

Answer 16

Heterozygous means that an organism has two different alleles of a gene
Carriers are always heterozygous

Question 17

example of biological evolution

Answer 17

The definition of biological evolution is: change in allele frequency in a population from one generation to the next.

Who? A population
What? The allele frequencies in that population
When? Over the time of a generation, which is the length of time it take for a group of individuals in this species to grow up and have offspring
Why? different species live for different lengths of time, and so generation lengths differ

Question 18

forces of evolution

Answer 18

1. natural selection- process by which the best-adapted individuals produce the most offspring. NOT RANDOM
2. genetic drift- random process in which chance plays a role in deciding which gene variants (alleles) survive RANDOM
3. gene flow- occurs when genes are carried from one population to another CREATES NEW VARIATION
4. mutation- also random

Question 19

natural selection

Answer 19

competition- food, water, shelter, mates

variation- traits of a population

Question 20

Direction Selection

Answer 20

one of the extremes in the population is more successful than the other extreme i.e. - Predator-Prey co-evolution

Question 21

Stabilizing Selection

Answer 21

selections against both extremes and selection for the average (i.e. human babies)

Question 22

Disruptive Selection

Answer 22

selection for the extreme and against the average

Question 23

Balanced Polymorphism

Answer 23

when individuals having a heterozygous genotype having greater reproductive fitness than those with homozygous genotypes. So selection for multiple alleles (i.e. Sickle-cell anemia and malaria)

Question 24

point mutation

Answer 24

a mutation affecting only one or very few nucleotides in a gene sequence

Question 25

chromosomal mutations

Answer 25

A chromosome anomaly, abnormality, aberration, or mutation is a missing, extra, or irregular portion of chromosomal DNA. It can be from an atypical number of chromosomes or a structural abnormality in one or more chromosomes

Question 26

gene flow

Answer 26

the spread of a gene through out a population
gene flow barriers are things like
-water (ocean)
think of the flowers around the great wall of China

Question 27

genetic drift

Answer 27

variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.
i.e. the flowers around the great wall of china are experiencing this

Question 28

Founders effect

Answer 28

the reduced genetic diversity that results when a population is descended from a small number of colonizing ancestors.
think of midgets in Amish society