Heredity: Why Do We Look Like Our Parents?

Practice flashcards covering the concepts of heredity, inherited versus acquired traits, Gregor Mendel's discoveries, DNA and chromosome structure, alleles, dominant and recessive traits, genetic variation, and mutations.

What is heredity (or inheritance)?

Heredity is when parents pass down genetic information to their offspring, determining traits such as eye color, height, blood type, and natural hair color.

What is the difference between inherited traits and acquired traits?

Inherited traits are passed through genes (e.g., blood type, natural eye color, natural hair texture, certain health conditions), whereas acquired traits are developed through experience and environment (e.g., playing an instrument, social manners, muscle size from exercise, political stance).

According to the presentation, what equation represents how our characteristics are formed?

$$\text{Genes} + \text{Environment} = \text{Our characteristics}$$

Who is known as the "Father of Genetics," and what was his background?

Gregor Mendel ($1822-1884$), an Austrian monk and scientist who studied pea plants and discovered patterns of inheritance that formed the foundation of modern genetics.

What four specific pairs of traits did Gregor Mendel study in pea plants?

Tall vs. short plants, purple vs. white flowers, green vs. yellow seeds, and round vs. wrinkled seeds.

What notable pattern regarding traits did Gregor Mendel discover through his breeding experiments?

Traits could disappear in one generation and reappear in another.

What is DNA (deoxyribonucleic acid) and what is its role in living organisms?

DNA is a molecule that stores the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms.

What is a chromosome, and how many chromosomes do humans normally have?

A chromosome is a thread-like structure made of DNA and protein found in the nucleus; humans normally have $23$ pairs, for a total of $46$ chromosomes.

What is a gene?

A segment of DNA that contains information to build a functional product, often a protein.

How do humans inherit chromosomes from their mother and father?

A mother contributes $23$ chromosomes through her egg cell and a father contributes $23$ chromosomes through his sperm cell, allowing offspring to inherit $46$ chromosomes in total ($1$ chromosome of each pair from each parent).

What are alleles?

Alleles are different versions of the same gene (for example, the round allele and wrinkled allele for the seed shape gene).

How do dominant and recessive alleles differ in expression and notation?

A dominant allele affects the trait when only $1$ copy is present and is represented with a capital letter; a recessive allele affects the trait only when $2$ copies are present and is represented with a lowercase letter.

In the eye color inheritance model presented, which genotypes result in brown eyes and which genotype results in blue eyes?

Brown eyes result from either the $BB$ or $Bb$ genotypes (where $B$ is dominant), while blue eyes require the recessive $bb$ genotype.

What is genetic variation?

Genetic variation means that individuals of the same species have differences in their genetic information.

What are the three main causes of genetic variation related to sexual reproduction?

Independent assortment (chromosomes distributed into sex cells in different combinations), random fertilization (different sperm and egg cells combine), and crossing over (chromosomes exchange DNA during meiosis).

What is crossing over?

A process during meiosis where chromosomes exchange DNA.

What is a mutation, and what effects can it have?

A mutation is a change in the DNA sequence; mutations can be neutral, harmful, or beneficial, and they can contribute to evolution.

What are the three main causes of DNA mutations mentioned in the lecture?

Replication errors (mistakes made during cell division), environmental damage (such as UV light from the sun, radiation, and harmful chemicals), and chemical breakdown (DNA naturally degrading over time within the cell).

What are the "3 things to remember" summarized at the end of the presentation?

1. Heredity passes genetic information between generations; 2. DNA contains genetic information organized into genes and chromosomes; 3. Genetic variation makes individuals different from one another.