GENETICS Notes – Review book Topic 3 Name ____________________

Genetics developed from curiosity about inheritance.

Genetics: The study of ______________________ (how traits are passed from one generation to the next

(inherited)

An ____________________trait of an individual can be determined by one genes, but is usually

determined by the interaction of many different genes…

_____________; A specific characteristic of an organism. Example: Flower color, eye color

• Cystic fibrosis, skin color, ___________________________________

Gregor _______________ - “Father of Genetics”- discovered that “factors” or alleles are

___________________ from parent to offspring; breeding _________________________________

Mendel’s Principles

1. During ____________________ (making gametes), the arms

of the chromosomes “_____________________________”

and __________________ increasing the genetic

possibilities of the offspring

2. When egg and sperm unite to form a zygote, their alleles

recombine and new combinations are formed - ________________________________________

Genes: segments of DNA that contain instructions to make _____________________

Each _________________ carries a separate piece of information

Hereditary information is contained in ________________, which are composed of ____________,

located in the _________________ of each cell. Chromosomes are found in the ________________of

each cell.

Gene Chromosome Theory

• Genes exist at definite loci in linear sequence on a ______________________and are found in

______________________________.

• Chromosome→ ________________ → ____________ → alleles→ ___________________

Mendel discovered that inheritance follows rules of chance.

________________: Alternate forms or __________________of a gene

Slightly different DNA codes and occur at the __________ location on

________________________ chromosomes

1. Dominant allele: The version of the gene that is expressed (observed) when both alleles are present.

o Symbolized with a ____________________ letter: Ex: A

2. Recessive allele: The version of the gene that is not expressed (not observed) when both alleles are

present. Symbolized with a _____________________________ letter: Ex: a

Genotype: The ________________________make-up of an individual.

The _______________________of the 2 alleles an individual has for a particular trait. Ex: AA, Aa, aa

1. Homozygous (______________) dominant - both ___________________genes are present. EX. AA

2. Homozygous (SAME) recessive – both _____________________ genes are present. Ex. aa

3. _________________________ – (hybrid) one dominant gene and one recessive gene are present. Ex. Aa

Carrier: Any individual who is __________________________________ for a trait.

They “carry” the _______________________________.

Phenotype: The ___________________________ aspects of a genotype

the ________________________characteristics

• The way a _____________________________________ is expressed/described.

Genotype -vs- Phenotype

TT tall pea plant (______________________________________________)

Tt tall pea plant (_______________________________________________)

tt dwarf pea plant (_____________________________________________)

A Punnett square is used to show the possible offspring _______________________

• Mendel’s Pea plants: tall (TT) –vs-. dwarf (tt) pea plants

• Gentotype:

• Phenotype:

I. DNA ___________________________

A. Building _____________________ =

1. ___________________________! (nucleotide)

2. Also known as _______________________

B. _____________________ (4 of them)

1. Each _______________ acid is made of _____ parts:

a) ___________ (________________________)

b) P____________________

c) ____ of 4 _________________ Bases:

(1) _____ = ___________

(2) _____ = ___________

(3) _____= ___________

(4) _____= ___________

C. DNA Shape

1. DNA IS ___________ _____________

2. _____________ TWIST TO FORM ___________- ____________

3. NITROGEN ___________ __________ TOGETHER TO MAKE _______ STRANDS

______ always binds with ______

______ always binds with ______

• A_______ T____________ G__ _C___________

• THIS IS CALLED _______________________________

Let’s Practice!

One strand of DNA has the sequence you see. What is the complimentary strand’s sequence???

G

G

T

A

C

G

C

C

T

II. DNA Replication ( _____________)

A. When does DNA need to be copied????

1. BEFORE any ________ _____________! (________________________________)

B. First, __________________________

C. Second, _____________ bring new _______________ to these strands (______________)

D. Third, you end up with ______________________________

E. DNA acts as a _________________or ____________________to make copies of itself!