Download Genetics Study Guide

Genetics Study Guide
Be sure you can write the answers to these 3 questions.
1. How are genes and Genes code for traits. Alleles are different forms of a gene. The alleles
alleles related to
we inherit determine our genotype and phenotype.
genotype and
phenotype?
2. If offspring are
The reproduction was asexual.
genetically identical to
the parent, what do
you know about the
reproduction?
3. Explain the process This process is called selective breeding. We select the desirable traits
in which humans
and breed those organisms to get an organism with both of those traits.
choose specific mates Example: Breed a seedless grape with a sweet grape and you get a
for organisms, such as seedless, sweet grape!!!!
dogs or roses, to
Breed a fast horse with a strong horse and you get a fast, strong horse.
produce organisms
with desirable traits.
1. Heredity
2. genetics
3. trait
4. purebred/truebreeding
5. gene
6. alleles
7. dominant allele
8. recessive allele
9. hybrid
10. probability
11. Punnett square
12. phenotype
13. genotype
14. homozygous
15. heterozygous
16. codominance
17. sperm
18. egg
19. meiosis
20. mutation
The passing of traits from parents to offspring
The scientific study of heredity
A characteristic that an organism can pass on to its offspring through
its genes
An organism that always produces offspring with the same form of a
trait as the parent….all offspring have the same traits as the parent
Instructions for an inherited trait…a segment of DNA on a
chromosome that codes for a specific trait
The different forms of a gene
An allele whose trait always shows up in the organism when the
allele is present
An allele that is masked when a dominant allele is present
An organisms that has two different alleles for a trait; an organism
that is heterozygous for a trait
The likelihood that a particular event will occur
A chart that shows all the possible combinations of alleles that can
result from a genetic cross
Review how to solve a Punnett square problem…see your notes.
An organism’s physical appearance, or visible traits
An organism’s genetic makeup or allele combinations
Having two identical alleles for a trait….DD or dd
Having two different alleles for a trait ….Dd
A condition in which neither of two alleles of a gene is dominant or
recessive...example of chickens with black and white feathers
A male sex cell
A female sex cell
The process that occurs in sex cells by which the number of
chromosomes is reduced by half.
A change in a gene or chromosome.
21. See page 152
Figure 3 on three ways
mutations can happen.
22. homologous
chromosomes page
125
23. Read page 125
about the influence of
the environment on
genes
24. See page 118 on
ratios
Substitution – one base is put in the place of another
Insertion – a base is added
Deletion – a base is left out
Chromosomes that carry the same set of genes
25. Page 131 – sexlinked disorders
****Why do sex-linked disorders occur more often in males?
Males have only one X chromosome and their Y chromosome has
no allele to mask the recessive sex-linked allele. So, males will
have the trait.
26. Know about
Mendel’s experiments
with pea plants and
how his experiments
relate to our
knowledge of genetics.
…pages 114-119
Mendel concluded that each trait he studied had two sets of
instructions, one from each parent.
Traits are passed from parents to offspring.
When a true-breeding/purebred plant self-pollinates, all of its
offspring have the same traits as the parent.
A self-pollinating plant fertilizes itself.
The principles of probability can be used to predict the results of
genetic crosses.
27. Sex chromosomes
28. Pedigree
Know what the shapes
of a pedigree
represent. See page
132 and your notes.
Determine sex/gender …………. Male = XY
Female = XX
A chart or diagram used to trace a trait through generations of a
family.
How do you know if the pedigree shows a sex-linked trait or a
trait found on chromosome pairs 1-22? If it is showing a sexlinked trait, males will not be shown as carriers. Males will only be
shown as having the trait or not having the trait.
If the trait is found on chromosome pairs 1-22, males can be carriers
as well as the females because there will be a dominant and a
recessive allele. Dd
Has one recessive allele for a trait and one dominant allele, but does
not have the trait.
Each allele has its own degree of influence
29. carrier
30. incomplete
dominance page 124
31. Sexual
reproduction and
asexual reproduction
32. Selective breeding
Genes are not the only influence on traits.
For example, how does the environment affect the height trait in a
person?
A ratio is the relationship between 2 different numbers that is often
expressed as a fraction
-Sexual reproduction – two parents and the offspring are genetically
different from both parents. Egg and sperm
-Asexual reproduction – one parent and the offspring are genetically
identical to the parent. Binary fission and budding
The process of selecting a few organisms with desired traits to serve
as parents of the next generation. Ex. Cross sweet grapes with
seedless grapes = a sweet, seedless grape
33. DNA
Pages 144-149
-The letters that represent the four bases are ATCG.
-Adenine pairs with Thymine
Cytosine pairs with Guanine
-Those pairs of bases make up the “rungs” of the DNA ladder.
-Write the matching bases for this DNA sequence: ATCCGGTAT
-The side of the DNA ladder are made of Phosphates and
Sugar/Deoxyribose
-To be copied, a DNA molecule splits down the middle and the
bases are used as a pattern for the next strand.
34. Nucleotides
35. Blood type alleles
Subunits of DNA which include a sugar, phosphate, and a nitrogen
base. See page 144.
Blood type alleles are A, B, and O. This is an example of a trait that
has multiple alleles.
Blood types are A, B, AB, and O. Type O is recessive.
36. Genetic
engineering
Read page 154 and write some information on genetic engineering.
37. Explain how
genes and alleles are
related to genotype
and phenotype.
Write your answer here for practice. You will find the answer on
the front of your study guide.
38. Explain how
chromosomes
determine sex/gender.
Draw the gender Punnett square and explain the results.