Jayden Wang - MedBio Ch. 5 Flashcards

DNA

DNA

Contains genetic material (genes) that code for proteins. One strand of this makes up a chromosome.

Body Cell

This type of cell contain 46 chromosomes (23 from each parent).

Homologous Chromosome

In sexual reproduction, it refers to the pair of chromosomes that are inherited from each parent. The two chromosomes for this pair have the same genes in the same order, but are slightly different. Females have 23 of these, and males have 22.

Interphase

During this period, cells prepare to divide by duplicating chromosomes.

Sister Chromatids

The identical copies formed by the DNA replication of a chromosome after interphase with both copies joined together by a common centromere.

Centromere

This cell structure links a pair of sister chromatids together during cell division. It also plays a key role in helping the cell divide up its DNA during division. Specifically, it is the region where the cell's spindle fibers attach and pull into place.

Karyotype

This is a stained image of homologous chromosomes which show the size and location of each gene/band on a chromosome.

Autosome (Autosomal Chromosome)

These produce body cells, or somatic cells. In the human karyotype, these form chromosomes #1-22. They’re organized by size, chromosome #1 being the largest.

Sex Chromosome (X/Y Chromosome)

These produce gametic cells which come in the form of sperm in males and eggs in females. In the human karyotype, this takes chromosome #23.

Sperm Cell

These gametic cells carry x or y chromosomes, are smaller than egg cells, and are the only cells in general that are mobile. They are formed at birth, but only mature during puberty.

Egg Cell

This type of gametic cell only carries x chromosomes, and its formation occurs within the body of a female embryo.

Diploid Cell

This type of cell contains two copies of every chromosome. In humans, this type of cell has 46 of these and is mathematically expressed with 2n. Cells such as body (somatic) cells and germ cells fall under this category.

Haploid Cell

Gametic Cells such as egg and sperm cells fall under this type of cell. There is only one copy of each chromosome, resulting in 23 chromosomes in this type of cell.

Gametogenesis

This is the final stage that haploid cells undergo in order to become fertilized.

Genetic Diversity/Variation

This is an advantage of meiosis and sexual reproduction. It refers to the many different types of genetic material within a population.

Independent Assortment

This process occurs during metaphase I, where homologous chromosomes pair up in a random manner. This results in genetic variation.

Crossing Over (Recombination)

This process occurs during prophase I, where homologous chromosome become so close that they exchange genetic material, which ensures that sister chromatids are no longer identical. This transpires approximately fifty-five times in meiosis in males, and about seventy-five times in meiosis in females which leads to genetic variation.

Fertilization

This process involves the union of a sperm and egg which fuse to form a diploid zygote to initiate prenatal development.

Trait

Physical characteristics that are passed down from parent to offspring.

Reasons Why Mendel Chose Pea Plants

1. Quick Reproduction Rate

2. Many Varieties

3. Pollination can be Controlled (Artificial Selection)

4. They DO NOT show an intermediate form (helps with identifying patterns through generations)

Female Parts of Pea Plants

1. Pistol

2. Stigma

3. Ovary

4. Style

Male Parts of Pea Plants

1. Stamen

2. Anther

3. Filament

These have pollen.

Genetic Cross

The mating of two individuals.

Pure Breed

Organisms that are either homozygous dominant or recessive.

Law of Segregation

When a gamete only receives one gene copy which is selected for at random.

Pea Plant Flower Color

Purple or White

Pea Plant Flower Position

Axial or Terminal

Pea Plant Seed Color

Yellow or Green

Pea Plant Seed Shape

Round or Wrinkled

Pea Plant Pod Shape

Inflated or Constricted

Pea Plant Pod Color

Green or Yellow

Pea Plant Stem Length

Tall or Dwarf

Allele

Variations of traits (genes) between homologous chromosomes.

Loci (Singular for Locus)

This indicates the location of a gene.

Gene

Portion of a sequence of DNA.

Genotype

Genetic composition of the organism. (Ex: AO, OL, Aa, or GO)

Phenotype

Physical form of an organism, or simply traits that are spelled out. (Ex: Yellow Pea Plant, Green Seed Color, Tall Stem Length, Purple Flower, etc.)

Monohybrid

A cross of one trait.

Dihybrid

A cross of two traits.