Inheritance and Genetic Crosses

Flashcards based on lecture notes about continuity and change, inheritance, and genetic crosses.

What happens during reproduction regarding gametes and zygotes?

Haploid gametes from each parent fuse to form a diploid zygote, inheriting information from both.

Where are male and female gametes found in plants?

Male gametes are in the pollen, and female gametes are in the ovary.

What is the F1 generation phenotype in a cross between homozygous round seed peas and homozygous wrinkled seed peas?

All F1 generation peas have heterozygous round seeds.

What does it mean for an allele to be dominant?

A dominant allele produces its characteristic phenotype when present.

What is a homozygous genotype?

Having two identical alleles of a particular gene.

What is a heterozygous genotype?

Having two different alleles of a particular gene.

What is continuous variation?

The combined effect of many genes and/or the effect of the environment on genes, which can be plotted as a normal distribution curve.

What factors define phenotypic output?

DNA sequence, epigenetics, environmental variables (e.g., nutritional sufficiency), and their interactions.

Define phenotypic plasticity.

The capacity to develop traits suited to the environment experienced by an organism by varying patterns of gene expression, without changes in genotype.

What are phenotypes?

The observable traits of an organism resulting from genotype and environmental factors.

What causes phenylketonuria (PKU)?

A deficiency of an enzyme that converts phenylalanine into tyrosine, leading to excess phenylalanine in blood. It is caused by a recessive allele.

Define gene pool.

The sum of all the population's genetic material at a given time.

What are single-nucleotide polymorphisms (SNPs)?

They give rise to different alleles containing alternative bases at a given nucleotide position within a locus.

Define codominance.

Heterozygotes have a dual phenotype where both alleles are simultaneously expressed.

What are the possible genotypes for blood group A?

I^A I^A and I^A i

What is incomplete dominance?

One characteristic is not dominant over the other, so both persist, resulting in an intermediate phenotype in offspring.

Which chromosome determines the sex of the zygote?

Sex chromosome in the sperm.

What combination of sex chromosomes leads to a female?

XX

What combination of sex chromosomes leads to a male?

XY

What is Sex linkage?

The phenotypic expression of an allele related to the sex chromosomes.

What can be deduced from pedigree charts?

Patterns of inheritance of genetic diseases.

What kind of inheritance causes continuous variation?

Polygenic inheritance and/or environmental factors.

Give an example of continuos variation.

Skin color or height in humans

Define discrete variation.

A discontinuous variation found in a number of distinct categories.

What are box-and-whisker plots used for?

To represent data for a continuous variable.

Describe the law of segregation.

During gamete formation, alleles for each gene segregate from each other, so that each gamete carries only one allele for each gene.

Describe the law of independent assortment.

Genes for different traits can segregate independently during the formation of gametes.

Describe the law of dominance.

An organism with at least one dominant allele will display the effect of the dominant allele.

What is a locus?

The place on the chromosome where a gene is located.

What are linked genes?

Gene loci are said to be linked if they are on the same chromosome.

What happens to unlinked genes during meiosis?

Unlinked genes segregate independently as a result of meiosis.