Crash Course on Heredity

Gregor Mendel, an Austrian monk, published his work on garden _________ in 1866. It became the basics for the study of genetics!

He formulated three laws of inheritance:

The Law of Dominance- When an organism has genes that call for two different versions of the same trait, the __________ gene will be expressed, while the other is masked.

Dominant allele (Capitalized)

Recessive allele (_________ case letters)

The Law of Segregation- alleles occur in pairs and are _________ from each other during gamete formation

The Law of Independent Assortment- during meiosis, genes for different traits are ____________ and distributed to gametes independently of one another.


Here is some vocabulary to be sure to know:

Allele: different ________ of the same gene

Phenotype: the form that is shown- the outward, _______ appearance of a trait

Genotype- the specific ________ make up of an organism

Homozygote- having two of the ______ alleles for a particular trait (pure)

Heterozygote- having two ___________ alleles for a particular trait. (hybrid)

Now it is time to study the probability of offspring using Punnet squares



Genetics Basics


All cells in the body contain the same ________.

  • Only some of these genes are turned ____ and others are silent.

Chromosome pairs carry alleles for the same trait.

  • We all have two alleles for each gene- one from each __________

Each chromosome has hundreds or thousands of genes.

  • Each gene codes for a particular _____________ (1 gene=1 protein).

Humans have 46 chromosomes, or ______ homologous pairs.

Sex chromosomes: in humans, females are _______ and males are ________

The Y chromosome is much __________ than the X, so it is missing many genes. This means many genes on the X chromosome do not have a partner and it will be expressed in males.

ex. color blindness, baldness, hemophilia

Gene Expression: While genes determine our traits, the environment can affect the ___________ of genes.

ex. fur color of Himalayan rabbit after exposure to cold air.

Genetic mutations in a cell can result in uncontrolled cell __________. Cancer can be caused by either heredity or environmental factors like radiation, chemicals or virus.


Transcription and Translation

Crash Course on Transcription and Translation

Transcription and Translation youtube

DNA is made of ____ bases: ATCG.

  • A three letter codon represents a specific __________ _______.
    • These amino acids are assembled into proteins.

Base pairs: A-T, C-G (in RNA, A-U and C-G)

Transcription = codes transfer from the _____ base sequence to the _____ base sequence in the nucleus

Translation = the _____ base sequence code transfers to _____ and specific amino acids are formed on the ribosome. A protein is synthesized.

Changes to DNA are called ________. They can only be passed on if they occur in reproductive cells (sperm or _____).


Genetic Technology

Selective breeding produces animals and plants with ________ traits (disease resistance,

Genetic engineering or gene splicing inserts _______ of one organism into the genes of another.

  • __________ are used to cut and copy the DNA segments.
    • ex. copying a gene into a plant that kills insects
  • Bacteria are often used.
    • ex. human _______ and growth hormones are grown artifically using bacteria

Gene Therapy- finding genes will mutations that cause disease can be fixed using hormones and enzymes from genetically engineered organisms.

Karyotype: a __________ of an organism's chromosomes

Gel Electrophoresis (or DNA fingerprinting) allows us to break down DNA into segments and ___________ DNA samples to determine if they are from the _______ source (crime scenes, taxonomy)






Possible gamete genotype
Hybrid vs. pure
Homo- vs heterozygous
Genotype vs phenotype
Incomplete dominance (red+white = pink)
Codominance (roan coat)
Multiple alleles (blood type)

Here is a FANTASTIC site for reviewing classical genetics.
There are online flashcards as well. Check 'em out.

Modern genetics Need a review site? How about the mutation class notes?
Sex chromosomes vs. autosomes
Sex-linked traits – follow using punnet squares
Pedigrees – be able to trace geno- and phenotype
polygenic vs. monogenic traits

Pedigree symbols website

Mutations – gene and chromosome
Amniocentesis and karyotyping
Genetic engineering (gene splicing)
Humulin production Get the Applied Genetics Classnotes
Selective breeding

Gene expression Wanna see the transcription and translation overheads from class?
Structure of DNA
Bases, double helix
Protein synthesis – know the process, ribosome
Environmental effect on gene expression