Science 10- Genetics: Chromosomes & Karyotypes and Introduction to Genetics

Flashcards covering the fundamental concepts of genetics, including DNA structure, chromosome organization, karyotypes, and Mendelian inheritance principles.

DNA

The molecule that stores genetic information which tells our cells how to look and function.

Genome

The complete DNA sequence in each cell of an organism.

Identical twins

The only exception to the fact that every organism of the same species has different genome sequences.

Human Genome Project Timeline

The project that took scientists 13 years, from 1990 to 2003, to map the human genome.

Human Genome Composition

Consists of about $3 \text{ billion}$ base pairs distributed in the $46$ chromosomes found in every cell of the human body.

Chromatin

Condensed strands of DNA that exist during most of the cell cycle.

Mitosis

The process where the cell's nucleus and genetic material begin to divide, causing chromatin to condense into distinct chromosomes.

Somatic cells

Human body cells that have $46$ chromosomes organized into $23$ pairs; includes most cells except sperm and egg cells.

Sex cells

Sperm and egg cells which contain only $23$ chromosomes.

Sex chromosomes

The $23\text{rd}$ pair of chromosomes, called $X$ and $Y$, which determine the genetic sex of an individual ($XX$ for biological female, $XY$ for biological male).

Autosomes

The remaining $22$ pairs of chromosomes (pairs $1$ to $22$) that are not sex chromosomes.

Homologous Chromosomes

Paired chromosomes that share similar features such as length, centromere location, and banding pattern, but are not identical.

Gene

A section of DNA that contains genetic information for the inheritance of a specific trait.

Alleles

Different forms of the same gene that account for differences in specific traits, such as straight hair versus curly hair.

Karyotypes

A particular set of chromosomes that an organism has, prepared by collected cell samples stained and stopped during metaphase of mitosis.

Genetics

The field of biology that studies heredity or the passing of traits from parents to offspring.

Gregor Mendel

An Austrian monk who founded the modern science of genetics through experiments using pea plants.

Self-fertilize

The process where the male gamete within a flower combines with the female gamete in the same flower.

True-breeding plants

Plants that consistently produce offspring with only one form of a trait, yielding predictable results.

Cross-fertilizing

The experimental process of transferring the male gamete of one flower to the female reproductive organ of a different pea plant flower.

$F_1$ generation

The first generation plants resulting from breeding true-breeding purple plants with true-breeding white plants.

$F_2$ generation

The second generation plants produced after allowing $F_1$ plants to self-fertilize, where the white trait reappears in a $3:1$ pattern.

Mendel's Laws

Three rules proposing that each plant has $2$ factors for each trait, each parent donates one factor, and one factor may be dominant over the other.

Law of Segregation

The principle that allele pairs on homologous chromosomes separate during meiosis so that each gamete carries only one allele from each pair.

Dominant allele

Represented with a capital letter, this trait is observed if an individual has $2$ copies or even just $1$ copy of the allele.

Recessive allele

Represented with a lower case letter, this trait can only be seen if the individual has $2$ copies of the allele.

Phenotype

The physical expression or observable characteristics of an organism's traits.

Genotype

The specific combination of alleles or genetic make-up an organism has for a trait.

Homozygous

An organism that has two identical alleles for a trait, categorized as either homozygous dominant or homozygous recessive.

Heterozygous

An organism that has two different alleles for a trait.

Mono hybrid cross

A genetic cross where the parents differ in only one specific trait being studied.

Punnett Square

A grid used by geneticists to determine the probability or likelihood of offspring inheriting specific traits from their parents.