Genetics Vocabulary Test Review

Genetics VocabularyTest Review

Learning goal (7.L.2) I will be able to describe, explain, and apply my knowledge of the relationship of the mechanisms of cellular reproduction, patterns of inheritance and external factors to potential variation and survival among offspring.

Acquired trait

A trait or characteristic that is developed or learned through life. Traits you aren’t born with. Traits GENERALLY not controlled by DNA.

Examples: walking, speaking English, dyed hair, pierced ears, glasses, skin cancer?

McDougal Littell p. C101

Inherited trait

A trait that you are born with which is passed to you through your parents’ genes. Trait that is controlled by DNA.

Examples: eye color, hair color, widow’s peak, dimples

Heredity

Passing of genes from parent to offspring. Not the passing of traits but the genetic code for the expression of traits.

Examples: genetic tendency for hair color, eye color, height, blood type

DNA

A chemical that contains information for an organism’s growth and functions. It is the genetic material in cells.

Example: deoxyribonucleic acid


Chromosome

The physical structure in a cell that contains the cell’s genetic material. DNA is wrapped around proteins like a thread around a spool and compacted into chromosomes.

Examples: 46 chromosomes mapped in the Human Genome Project

McDougal Littell p. C75McDougal Littell p. C147

Gene

A unit of heredity that occupies a specific location on a chromosome and codes for a particular product.

Examples: Genes code for the expression of traits. Genes come from your parents. BB, Bb for brown eyes or hair


Allele

The various forms of the same gene

Examples: A DNA sequence that codes for a gene such as BB, Bb, Tt, Gg, Yy. May occur in pairs or multiples.


Genotype

Genes an organism has. It describes the genes that code for traits.

Examples: GG, Ss, TT

CC, Cc

cc

CC, Cc, or cc for determiningTongue rolling.

Phenotype

Physical traits that are observed or present.

Examples: Blue eyes, sickle cell anemia

Curly or straight hair

Dominant

An allele that is expressed in the phenotype when only one copy is present in the genotype.

Examples: brown hair, brown eyes, tall, tongue roller

RR or Rr

Recessive

An allele that is expressed in the phenotype only when two copies of it are present.

Example: blue eyes, blonde or red hair, short

It is possible for two brown-haired parents to have a blonde-haired child.


Gregor Mendel

An Austrian monk who performed the first major experiments investigating heredity during the mid-1800s.

Examples: investigated the inheritance of traits among pea plants

Prentice Hall p. C80

Pea Plants McDougal Littell p. C105

Punnett square

A tool for illustrating how the parents’ alleles might combine in offspring. Shows how patterns of heredity can be predicted.


Monohybrid Cross

A genetic cross using a single trait with two alleles.

Example: The allele for green pod color (G) is dominant and the allele for yellow pod color (g) is recessive. The cross-pollination between a P generation green pod plant and a P generation yellow pod plant results in all green offspring. All genotypes are (Gg).

Homozygous

A trait where both alleles are identical. Another term is purebred which means an organism that produces offspring with the same form of a trait as the parent.

Example: SS tt bb

The dominant trait for eye color is brown, represented by BB. All other eye colors – blue, grey, green, and hazel – are recessive traits, represented by bb. A homozygous brown eyed person would have the BB gene, while a homozygous blue eyed person would have the bb gene.

Heterozygous

A trait where the two alleles are different. Hybrid is another term used to describe this trait.

Examples: Hh Tt Cc

Mutation

Any change in DNA

Causes: errors when DNA is copied before cell division or environmental such as exposure to harmful chemicals, x-rays, or UV radiation

Albino Loggerhead turtle @ Pine Knoll Shores Aquarium

Genetic Disorder

A disease or condition that results from mutations that affect the normal functioning of a cell.

Examples: inherited (Tay-Sachs disease, Cystic Fibrosis, Albinism)

Albinism

Sickle Cell Anemia

A recessive disorder in which the red blood cells take on a sickle shape. It takes two copies of the recessive allele to be expressed.


Hemoglobin

A protein that carries oxygen in red blood cells. Important for oxygen delivery to the body tissues. Without enough oxygen tissues become damaged.

Example: normal hemoglobin undergoes mutation to code for sickle cell anemia


Huntington’s Disease

Huntington disease is a disorder in which nerve cells in certain parts of the brain waste away, or degenerate. This disorder is passed down through families and only requires one copy of the dominant allele to have the disease.

Pedigree

A diagram of family relationships that includes two or more generations. Used to track genetic disorders as to who has the disease and who is a carrier.

Genetic Variation

The genes of organisms within a population change.

Sexual reproduction

A type of reproduction in which male and female reproductive cells combine to form offspring with genetic material from both cells. Produces genetic variation.

Examples: multicellular organisms---humans, animals, birds, fish, certain plants

Asexual reproduction

One organism produces one or more new organisms that are identical to itself and live independently of it.

McDougal Littell p. C88 McDougal Littell p. C89

Meiosis

A special kind of cell division that produces haploid cells (gametes). These cells contain half the usual number of chromosomes (one from each pair).


Prophase l

Chromosomes condense. The nuclear membrane disappears.


Metaphase l

Chromosomes arrange as pairs in the middle of the cell.


Anaphase l

The homologs of each chromosome pair separate and are pulled to opposite ends of the cell.


Telophase l and Cytokinesis

The cell divides into two daughter cells.


Prophase ll

Each chromosome is made up of two or more copies of a homolog, two chromatids.


Metaphase ll

Each chromosome lines up in the middle of the cell.


Anaphase ll

The chromatids split forming individual chromosomes. The separated homologs are pulled to opposite ends of the cell.


Telophase ll and Cytokinesis

Both cells divide, producing four 1n (haploid) cells.


Fertilization

The process that takes place when a sperm and an egg combine to form one new cell.


Gametes

Cells that contain half the usual number of chromosomes (one chromosome from each pair.)

Examples: 1n cells (haploid cells)

Egg – a gamete that forms in the reproductive organs of a female

Sperm – a gamete that forms in the reproductive organs of a male

Vocabulary Word of the Week

Dawdle (verb)Definition: to waste time; to be idle; to spend more time doing something than is necessary

So quit dawdling and be sure you spend time studying for the Genetics Test!

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Genetics Vocabulary Test Review