Download userfiles/1290/Genetics Review Sheet - Answer Key

Name: _______________________________________ Block: ______
Genetics & Heredity Review Sheet:
Define & give example :
Genotype – An organism’s __genetic___ ___makeup________ Ex: __BB or Gg_
Phenotype – An organism’s __physical _ __appearance_____ Ex: __Blue eyes_
Dominant gene – The trait that will show up when _it’s allele is present in
the genotype________________. We show it by using __CAPITAL__ letters.
Recessive gene – The trait that will show up only when _it is the only allele
present (no dominant allele to “take over). We show it by using
_lowercase_letters.
Answer:
Where do an organism’s traits come from? Directly from _parents______.
Two forms of the gene for the same trait are called __alleles_________.
Where are genes located? ____on chromosomes_____________________.
Where are chromosomes located? ____DNA (in nucleus)________________.
DNA is the __blueprint_____________ for the organism.
# of chromosomes a normal (not gametes) human cell has ? _46 (23 pairs)
Be able to do a Punnett Square:
Parents: BB and Bb (for Brown eyes B and blue eyes b)
B
What % will have brown eyes? 100%
BB
What % will have blue eyes? 0%
B
What % are homozygous? 50%
What % are heterozygous? 50%
Bb
b
B
BB
Bb
Asexual vs. Sexual Reproduction:
Explain two advantages and disadvantages for each type of reproduction:
Sexual
Advantages:
Disadvantages:
produces genetic variety
have to find mate &
& species can survive
takes longer
changing environments.
Asexual
does not have to find
No genetic variety;
mate & takes less time.
cannot survive change
What evidence in a species would indicate the type of reproduction involved?
If asexual reproduction, all of the species would be exactly alike (looks, genes,
etc). If sexual reproduction, there would be a variety of traits.
Give an example of a type of organism that reproduces using each method.
Asexual – Bacteria, many single celled organisms
Sexual – Humans, many plants, dogs, cats, etc.
Mitosis vs. Meiosis:
Mitosis
# of cells at the end of the process
# chromosomes at the end
Type of cell that does this
Genetic variety: are cells genetically the
same or different?
Meiosis
2
4
Full amount
(46 for
humans)
“Regular” cells
(skin, blood,
etc)
Half amount
(23 for
humans)
Same
Different
Gametes
(egg/sperm)
Give examples of:
Genetic engineering: A glowing tobacco plant or cloned sheep
Mutation: Sickle cell anemia (blood disease from change in DNA)
Learned/Inherited Behaviors: Talking is learned, making sounds is
inherited