Chapter 14: Mendel and the Gene Idea

Question 1

Law of segregation (Mendel’s 1st law)

Answer 1

If 2 alleles separate during gamete formation, they end up in different gametes

Question 2

Dihybrid Cross

Answer 2

Mating between to orgs who are heterozygous for two traits

Cross between 2 pure bred orgs for two characters

Question 3

4 Concepts of Mendel’s Model

Answer 3

1. alternative versions of genes account for variations in in hearted characters
2. for each character, an org inherits 2 alleles (one from each parent)
3. If there are two alleles, the dominant one will be expressed
4. If 2 alleles separate during gamete formation, they end up in different gametes (law of segregation)

Question 4

Test cross

Answer 4

When you cross a homozygous recessive organism with one of dominant phenotype but unknown genotype

Question 5

Pleiotropy

Answer 5

When one gene affects multiple things/has multiple, unrelated effects

Question 6

Gene

Answer 6

Hereditary determinant for a trait

Question 7

Multiplication rule

Answer 7

Probability of two or more events occurring TOGETHER is the product of their individual probabilities

Question 8

Particulate Theory

Answer 8

Mendel’s idea that parents pass on discrete, heritable units (genes)

Question 9

Character

Answer 9

Heritable feature that varies among individuals

Question 10

Reciprocal cross???

Answer 10

Cross where the phenotypes of the male and female are reversed compared with prior cross

Question 11

Law of Independent Assortment (Mendel’s 2nd law)

Answer 11

The idea that inheritance of one allele doesn’t necessary effect inheritance of another

Unless they’re on the same, homologous chromosome (genes located near each other tend to get inherited together)

Question 12

Trait

Answer 12

Each variant for a character

Any characteristic of an individual

Question 13

Co-dominance

Answer 13

Type of degree of dominance like blood type

Question 14

Allele

Answer 14

Different versions of the same gene

Variations on the same kind of gene

Question 15

Polymorphic trait

Answer 15

Appears commonly in two or more different forms (like flat or wrinkled seeds)

Question 16

Heterozygous

Answer 16

Two genes with different alleles (that code for the same character)

Question 17

Autosomal inheritance

Answer 17

Inheritance that is perpetuated by non-sex chromosomes

Question 18

Genotype

Answer 18

The genes present in an organism

Question 19

Pangenesis

Answer 19

Darwin’s (false) idea that “gemmules” secreted by all the body’s cells aggregate in the sex organs and combine/blend together with a partner’s to make a baby

Question 20

Epistasis

Answer 20

When a gene on one locus effects a gene on another locus

Question 21

Homozygous

Answer 21

Two genes with identical alleles

Question 22

Monohybrid Cross

Answer 22

Cross between 2 heterozygous orgs for one character

Question 23

Hybrid

Answer 23

Offspring from matings between breeding parents that differ in one or more traits

Question 24

Addition rule

Answer 24

probability that any one of two or more exclusive events will occur is the SUM of their individual probabilities

Question 25

Phenotype

Answer 25

The genes that get expressed in an organism (particularly r/t physical appearance)

Question 26

Degrees of dominance

Answer 26

When an allele is not completely dominant or recessive

Question 27

"heritable factor"

Answer 27

what Mendel called what we know call a gene

Question 28

Polygenic inheritance

Answer 28

When multiple genes effect a single phenotype

Question 29

Pure line

Answer 29

Organisms that produce offspring identical to themselves when they’re self-fertilized (bc they have homogenous alleles for a trait)