Biology Lesson 8: Genetics, Part 1

Question 1

Mendel’s experiments with pea plants

Answer 1

1. Self-pollination: when a plant has both gametes and fertilizes itself
2. the anthers contains the male gamete and the pistol contains the female gamete
3. cross-pollination: the male gamete of one plant fertilizes the female gamete of another plant
4. purebred: a plant which has only been self-pollination

Question 2

Dominant versus recessive

Answer 2

1. dominant trait: a genetic trait that has a higher likelihood of being passed on to the next generation
2. recessive trait: a genetic trait that is not as likely to be passed on to the next generation as the dominant
3. alleles: different versions of the same genes
4. genotype: the combination of alleles carried by an organism all genes collectively, whether dominant or recessive
5. phenotype: what the organism actually looks like
6. homozygous: when an organism has two copies of the same allele–either both dominant or both recessive
7. heterozygous: when an organism has two different copies of an allele–one dominant and one recessive

Question 3

The law of segregation

Answer 3

the segregation of the alleles (dominant and recessive) into the gametes of an organism is random

Question 4

Genetic crosses

Answer 4

Punnet square
test cross
monohybrid crosses

Question 5

Punnet square

Answer 5

a simple way to depict genetic crosses and determine the probability of a specific genotype of phenotype

Question 6

Test cross

Answer 6

the process of observing the offspring of a plant to determine if the parent plant is homozygus or heterozygus

Question 7

Monohybrid crosses

Answer 7

crosses that only look at one trait of an organism

Question 8

Law of independent assortment:

Answer 8

alleles of two (or more) different genes are sorted into gametes independently of one another

Question 9

Dihybrid cross:

Answer 9

the type of cross that deals with 2 different pairs of traits at the same time

Question 10

When does incomplete dominance occur?

Answer 10

when two alleles are both expressed resulting in a blended phenotype

Question 11

When does codominance occur?

Answer 11

when two alleles for a gene are both expressed but the characteristics are seen side by side

Question 12

Sex linked traits

Answer 12

Females have XX chromosomes; males have XY chromosomes

Question 13

Carrier

Answer 13

an individual who doesn’t exhibit a trait but carries the gene for the trait– the trait is in the genotype but not the phenotype for that individual

Question 14

Polygenic inheritance:

Answer 14

when a single trait is controlled by multiple sets of genes