Genetics and Inheritance Flashcards

Flashcards covering key concepts from lecture notes on genetics, inheritance patterns, and related topics.

What is the means of inheritance in sexual lifecycles?

Production of haploid gametes in parents and their fusion to form a diploid zygote.

When do haploid gametes need to be produced to avoid doubling the chromosome number in offspring?

During meiosis I, when homologous chromosomes separate.

What is Mendel's Law of Segregation?

Law of segregation: 2 alleles of each gene separate into different haploid gametes during meiosis.

What is Mendel's Law of Independent Assortment?

Law of independent assortment: inheritance of 2 genes is independent.

Why are flowering plants an excellent model organism for conducting genetic crosses?

Plants do not move, self-fertilization can be prevented, and the process of fertilizing a plant is simple.

What is the P generation?

The parents

What is the F1 generation?

The offspring inside the seeds

What is the F2 generation?

The cross of the F1 generation

What are alleles?

Different versions of genes

What is a SNP?

Single nucleotide polymorphism (one base is changed)

What is a genotype?

The specific allele combination that an organism has (DD, Dd, dd)

What does Homozygous mean?

When both alleles that the organism has are the same

What does Heterozygous mean?

When both alleles that an organism has are different (Dd)

What is the phenotype?

The observable traits of an organism

What causes phenotype?

Genetic and Environmental factors

What is Phenotypic plasticity?

Organisms adapt to their environment by changing their expression of certain genes, giving a temporary change to their phenotype.

What happens in a dominant-recessive inheritance pattern?

The allele masks the other

Explain dominant-recessive patterns in terms of protein synthesis

Genes code for proteins, and recessive alleles often result from mutations to a dominant allele so it does not produce a functional protein.

What is PKU?

A disease caused by a recessive allele located on chromosome 12 where the enzyme phenylalanine hydroxylase has a mutation and doesn’t produce a functioning enzyme.

What is a gene pool?

All the genes of all the individuals in a sexually reproducing population.

What is an allele?

Alternate forms of a gene, usually due to one or a very small number of bases being different.

What is a SNP (single nucleotide polymorphism)?

The position in a gene where different bases can be present.

What is the S-gene in apples?

A system in apples that prevents self-pollination and the change of inbreeding.

What are multiple alleles?

When there are three or more alleles for the same gene.

What is an example of multiple alleles?

The ABO blood types in humans.

What is Co-dominance?

Neither allele has dominance (masks) the other; there is a different phenotype for the heterozygote that is distinct (not an intermediate).

What is incomplete dominance?

Neither allele is dominant over the other, but the heterozygote phenotype is intermediate.

How is sex determined in humans?

Sex in humans is determined by the X and Y chromosomes.

What is the role of the SRY gene in sex determination?

The SRY gene is found on the Y chromosome and codes for the DNA-binding protein TDF, which binds to DNA and acts as a transcription factor.

What causes sex-linked characteristics (or diseases)?

Genes located on the sex chromosomes, either the X or the Y.

What is Hemophilia?

A genetic disease that is implicated with inability to make Factor VIII, a protein promoting blood clotting.

Why are pedigree charts useful?

To analyze pedigree charts in order to determine patterns of inheritance.

What is continuous variation?

A continuous range of types is possible; all intermediate values are included.

What is discrete variation?

Separate categories of variant, with no intermediates between them.

What pieces of information can you obtain from a box and whisker plot?

Minimum value (excluding outliers), the lower quartile, the median, the upper quartile, the maximum value (excluding outliers), the interquartile range and whether the data is skewed.

What patterns of inheritance exist in plants and animals?

Genetic crosses show how haploid gametes can join to form diploid zygotes with various combinations.

What is the molecular basis of inheritance patterns?

The X chromosome is much larger than the Y chromosome so it carries more genes. Polygenic inheritance leads to continuous variation in a trait.