Transcript Genetics Vocabulary

Genetics Vocabulary
Test 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.
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?
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Acquired 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
Inherited trait
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
Heredity
A chemical that contains information for an
organism’s growth and functions. It is the genetic
material in cells.
Example: deoxyribonucleic acid
DNA
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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
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Chromosome
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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
Gene
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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.
Allele
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Genes an organism has. It describes the genes that
code for traits.
Examples: GG, Ss, TT
CC, Cc, or cc for determining
Tongue rolling.
CC, Cc
Genotype
cc
Physical traits that are observed or present.
Examples: Blue eyes, sickle cell anemia
Curly or straight hair
Phenotype
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
Dominant
An allele that is expressed in the phenotype only
when two copies of it are present.
Example: blue eyes, blonde or red hair, short
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It is possible for two brown-haired parents to have a blonde-haired child.
Recessive
An Austrian monk who performed the first major
experiments investigating heredity during the mid1800s.
Examples: investigated the inheritance of traits
among pea plants
Gregor Mendel
Prentice Hall p. C80
Pea Plants
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A tool for illustrating how the parents’ alleles
might combine in offspring. Shows how patterns of
heredity can be predicted.
Punnett square
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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).
Monohybrid Cross
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.
Homozygous
A trait where the two alleles are different. Hybrid is
another term used to describe this trait.
Examples: Hh Tt Cc
Heterozygous
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
Mutation
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
Genetic Disorder
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.
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Sickle Cell Anemia
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
Hemoglobin
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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.
Huntington’s Disease
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.
Pedigree
The genes of organisms within a population
change.
Genetic Variation
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
Sexual reproduction
One organism produces one or more new organisms
that are identical to itself and live independently of it.
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Asexual reproduction
A special kind of cell division that produces
haploid cells (gametes). These cells contain half the
usual number of chromosomes (one from each pair).
Meiosis
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Chromosomes condense. The nuclear membrane
disappears.
Prophase l
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Chromosomes arrange as pairs in the middle of
the cell.
Metaphase l
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The homologs of each chromosome pair separate
and are pulled to opposite ends of the cell.
Anaphase l
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The cell divides into two daughter cells.
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Telophase l and Cytokinesis
Each chromosome is made up of two or more
copies of a homolog, two chromatids.
Prophase ll
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Each chromosome lines up in the middle of the
cell.
Metaphase ll
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The chromatids split forming individual
chromosomes. The separated homologs are
pulled to opposite ends of the cell.
Anaphase ll
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Both cells divide, producing four 1n (haploid)
cells.
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Telophase ll and Cytokinesis
The process that takes place when a sperm and an
egg combine to form one new cell.
Fertilization
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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
Gametes
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!
Vocabulary Word of the Week