Mendel's Laws of Inheritance

Question 1

Inheritance

Answer 1

Transmission of characteristics to offspring. How traits are passed on to offspring.

Question 2

Dominant and Recessive Traits

Answer 2

Mendel’s observations are differences in prevalence of traits. Some traits are more likely to be passes on than others. Genes are the factors that will determine what offspring will inherit. Each gene comes in a varieties called, “alleles.” Ex: Gene for seed color in pea plants has allele for green and another for yellow.

Question 3

Dominant

Answer 3

two alleles for a gene are always expressed or shown by the organism if it is present and masks the recessive allele. Most powerful trait or the allele for that trait.

Question 4

Recessive

Answer 4

Recessive allele is only expressed when both alleles are recessive. Traits that are masked if dominant alleles are also present, also refers to the allele for that trait.

Question 5

Mendel’s third law of dominance

Answer 5

The Law of Dominance. Dominant trait is always expressed or shown by the organism while recessive is masked. Ex: Seed color the green allele is dominant and the yellow allele is recessive.

Question 6

Mendelian inheritance

Answer 6

Inheritance of traits that follow Gregor Mendel’s two laws and the principle of Dominance.

Question 7

Punnett square

Answer 7

A square diagram is used to determine the various genotype combinations that may be passed from parent to offspring and their likelihood of occurring.

Question 8

Inheritance of Gene Pairs I

Answer 8

Most living things inherit one of each pair of chromosomes from each parent. Humans have 23 pairs of chromosomes from each parent for a total of 46 chromosomes. Offspring inherit two copies of each gene from each parent. They will have two alleles for each gene. Combination of two alleles is called, “genotype.”

Question 9

Genotype

Answer 9

The genetic makeup of an individual. The combination of two alleles.

Question 10

Homozygous

Answer 10

A chromosome that contains two alleles that are the same, the genotype is called homozygous. The state of carrying a pair of identical alleles of a gene. Ex: AA or aa.

Question 11

Heterozygous

Answer 11

Chromosome that contains two different alleles, that genotype is called “heterozygous.” The state of carrying different alleles of a gene. Ex: Aa

Question 12

Phenotype

Answer 12

Alleles present in an organism determine “phenotype.” Is the expression of genes for that trait. Are visible traits. Ex: seed color. and unseen traits like blood type. Physical appearance of a trait formed by genetics and environment.

Question 13

Inheritance of Gene Pairs II

Answer 13

Offspring express either a dominant or recessive phenotype based on the two alleles inherited for a trait. Inherited traits pass from parent to offspring through gametes (eggs or sperm). Each gamete carries carries 1 chromosome of the chromosome pair (and only one copy of each gene). When egg and sperm fuse together (fertilization), a cell with two copies of each chromosome ( and two copies of each gene) results. Zygote has 46 chromosomes. This is Mendel’s law of Heredity.

Question 14

Nonheritable Traits

Answer 14

Traits such as culturally influenced behavior are not inherited as part of the genome. These are nonheritable traits not coded for in genes.

Question 15

Using Punnet Squares

Answer 15

Predict the likelihood of traits in offspring. A Punnett square is a chart that can be used to determine ratios of the genotypes of offspring from a reproductive cross. You must know the genotypes of the parents and are represented by two letters. Capital letters form dominant alleles and lower-case letters will represent recessive alleles. Ex: In pea plants Purple is (P) is the dominant flower and white is (p) and is recessive.

Question 16

Pea Plant Genotypes I

Answer 16

Genotypes of two parent pea plants. First parent has a genotype of (PP), which means 2 dominant alleles. This plant would express the dominant trait or phenotype of purple flowers. The second genotype would have a genotype (pp) and express the phenotype for white flowers because there is no dominant allele present and considered homozygous recessive. When two parents are crossed each parent contributes 1 allele (P) and (p) combined. They will then have a heterozygous genotype (Pp). They will have a phenotype of purple because they have a dominant allele.

Question 17

Pea Plant Genotypes II

Answer 17

Consider two heterozygous genotypes (Pp and Pp) flowers using a Punnett Square. Sperm genotype (Pp) placed at the top of the Punnett square and the egg (Pp) placed on the side. F2 Genotypes are (PP) is 25%, 50% of offspring will be (Pp) and 25% is (pp). 75% of the offspring will have purple flowers and 25% will have white flowers.

Question 18

Dihybrid cross

Answer 18

A cross between heterozygous parents at two specific genes.The inheritance of two traits can also be studied using a Punnett Square. Illustrates Mendel’s Law of Independent Assortment. Tracks the inheritance of two different traits and starts with a parental cross of two true-breeding or homozygous organisms. One parent is homozygous dominant for both traits and the other parent is homozygous recessive for both traits. Ex: F1 generation (YyRr) show two dominant traits of yellow seeds. F2 generation shows both dominant and recessive traits. It shows Law of independent assortment because alleles are not inherited together. Allele (Y,y,R and r) is inherited separately or independently and supported by for phenotypes.

Question 19

Gametes

Answer 19

have a unique combination of genetic material due to meiosis. Crossing over and random assortment of homologous chromosomes bring about the shuffling of genetic material during formation of gametes.

Question 20

non-Mendelian inheritance

Answer 20

Inheritance of traits that do not follow the Mendelian patterns of inheritance. Occurs when their are other factors other than dominant and recessive alleles in play. factors include multiple alleles (blood groups A, B, O). Incomplete dominant- recessive relationships that lead to an intermediate (red and white alleles making pink flowers), co-dominance (AB blood group express both A and B proteins), and interactions between genes called “epistasis” when one of the genes is carried on one of the sex chromosomes X or Y (a.k.a differntial expression).