Chp. 4 GENETICS: the scientific study of heredity

Who was Gregor Mendel?
A priest in the mid nineteenth century who tended a garden in central European monastery.

What did Mendel do?
He experimented with thousands of pea plants to understand the process of heredity and was the founder of the discovery of genetics

What are Female sex cells?
eggs

What are male sex cells?
sperms

what makes female and male sex cells?
female= pistil
male=stamens

Mendel’s 1st Experiment: Purebred tall pea plants crossed with what?
Purebred short pea plants

What was the outcome of the first experiment?
all tall pea plants(offspring)

what was the outcome of the 2nd experiment?
1/4= short pea plants
3/4=tall pea plants

What did he learn from the experiment?
he learned that some pea plants can have a short recessive traits

dominant allele?
one who’s trait always shows up in the organism when the allele is present.

recessive allele?
is hidden whenever the dominant allele is present.

which allele has the capital letter?
dominant allele

which allele has the lower case version of the letter?
recessive allele

the first letter of the Genotype is recessive or dominant?
DOMINANT

in a punnette square, where is the male’s genotype’s listed? and where is the female’s?
Male= top of punnette square
Female= side left of punnette square

phenotype?
an organisms physical appearance or visible traits

Genotype?
an organisms genetic makeup or allele combination

can 2 organisms look the same & have a different genotype?
yes

homozygous?
an organism that has 2 identical alleles for a trait(SS)

heterozygous?
an organism that has 2 different alleles for a trait (Ss).

codominance?
the alleles that are neither dominant nor recessive

In a genetic cross, the allele that each parent will pass on to its offspring is based on what?
probability

Punnette Square?
a chart that shows all the possible combinations of alleles that can result from a genetic cross.

probability?
a number that describes how likely it is that an event will occur.

hybrid?
organism that has 2 different alleles for a trait.

Gene?
the factors that control a trait

Alleles?
The different forms of a gene

Fertilization?
the process by which egg and sperm join

purebred?
the offspring of many generations that have the same trait.

Heredity?
the passing of physical characteristics from parents to offspring

trait?
each different form of a characteristic

genetics
the scientific study of heredity