Heredity
1. Give an example of how heterozygous, homozygous dominant, and homozygous recessive alleles are written.
Heterozygous: Aa
Homozygous dom: AA
Homozygous rec: aa
15. What are the 4 nitrogenous bases and how do they pair up?
Adenine (A), thymine (T), cytosine (C), guanine (G)
A-T
C-G
19. What are the 2 sources of influence on all traits?
genes and enviornment
18. T/F: Animals can be bred for any trait including patience
True (ie: foxes bred in Russia to make good pets, cows bred for greater patience while being milked, etc.)
21. Why is human evolution still only a theory rather than law or fact
We cannot prove human evolution in a lab setting because it takes too long, however, there is significant evidence in nature and related lab studies
2. Describe a phenotype v. a genotype.
A phenotype is the physical appearance of specific alleles (brown eyes), a genotype is the combination of specific alleles (Bb)
3. What are introns v. exons?
Exons are parts of DNA that code for proteins while introns fo not.
16. Ally and Sally are MZ twins who were separated at birth, they met up later in life and have more personality traits that are the same than different ones. Personality has a _________ heritability.
high
20. Are innate traits like swallowing and other reflexes affected by envt?
Yes, ALL traits are affected by both genes and envt.
22. What is the correct way to write scientific name for a cockatoo:
cacatua goffini
Cacatua goffini
Cacatua goffini (but underlined)
11. Explain the difference between mitosis v. meiosis (general steps included, final outcome, what each is responsible for)
Mitosis: chromosomes duplicate in the cell and split into identical cells resulting in daughter cells identical to the original cell (in humans 23 pairs of chromosomes), responsible for all autosomes
Meiosis: the same first cells of mitosis but then split again without duplicating resulting in sister cells with half the original amount of chromosomes (in humans 23 chromosomes rather than 23 pairs of chromosomes), responsible for gametes
4. Explain the process of translation.
tRNA with an anticodon "read" nucleotide bases in groups of 3s (codons) and build amino acids according to the code
5. Describe the difference between heredity and heritability.
Heredity: how genes are passed down within families
Heritability: how genes describe the difference between people/ populations
17. An adoptee has lots of personality traits in common with their adoptive parents and little in common with their birth parents. Personality has a __________ heritability. How do you know?
Low, heritability is the percent of variance that can be explained by genes rather than the environment, an adoptee having more in common with adoptive parents is explained more by environmental factors than genetic factors
23. Birds and butterflies both have functional wings allowing them to fly in response to pressures in their relationship be included in phylogeny? Why or why not?
Birds and butterflies can both fly to access food and escape predators, but they did not gain this trait from a common ancestor. The wings are analogous not homologous so it has nothing to do with common ancestry
12. Huntington's disease is an autosomal dominant disease. Can two affected parents have an unaffected child? Draw a punnett square on the whiteboard.
Yes, if both parents have a heterozygous genotype there is a 25% chance of having an unaffected child.
10. Describe the 4 different types of mutations and give an example on the whiteboard of how they would affect the original strand
"ATT CTG ATG ..."
Point: a single nitrogenous base is replaced for another
UAA GCC UAC ...
Deletion: an entire codon is removed from the strand
UAA UAC ...
Insertion: an entire codon is added to the strand
UAA AUC GAC UAC ...
Frameshift: a single nitrogenous base is either added or removed without being replaced
UAA GCU AC. ...
6. Fix this sentence and explain why it is wrong:
Height has a heritability score of 0.80, 80% of your height is a result of your genetics and 20% is a result of your environment.
The whole thing is wrong, you cannot turn heritability inwards, heritability is how genes describe the differences among a population not what makes an individual who they are.
7. What does "different genes interact with different environments differently" mean?
That the outcome of a certain trait is dependent on the interaction of different genes and different environments, The same genes may be expressed differently in different environments, and different genes can be expressed differently in the same environments.
24. What does it mean if species are close together on a phylogenetic tree?
The closer they are the more recent their common ancestor are. Humans and bonobos are close together and closely related, their common ancestor is more recent than humans and dolphins
14. Two part question:
(1) Why are women less likely to be colorblind? (2) Draw a punnett square on the whiteboard that shows how a woman can be colorblind.
(1) Colorblindness is a recessive x-linked disorder meaning the gene is carried on the x chromosome, women have 2 x chromosomes so in order for women to be colorblind they need to be homozygous recessive which is less common, even if they have one of the faulty alleles they have another x chromosomes to potentially make up for the faulty one.
(2) a woman can be colorblind in 2 scenarios:
- a colorblind father and a carrier mother
- a colorblind father and a colorblind mother
13. Why do we get frequent variants of viruses?
Once a virus enters a host cell it is really good at replicating itself and does so way more often than many other organisms, therefore, allowing more possibility for mutations, hence, variants.
9. How can the heritability of a trait change over time? In your explanation use hair color as an example.
A trait may have different influences of genes v. envt among people at different ages/ times/ time periods. ie: hair color at a young age may have a high heritability score, but later in life a lower heritability score due to envt. factors like hair dye, stress, etc.
8. Draw the maze dull/ maze bright rats graph and describe what it means.
That different genes interact with different environments differently
25. Darwin's theory of evolution by natural selection was inspired by the different beak shapes he observed among the finches of the Galapagos islands. How and why did these different beak shapes develop?
Certain types of food were more abundant in diff areas of the Galapagos to survive, the birds needed to be able to access the type of food available in their area those birds whose beaks were especially suited to the food in their region were more likely to survive and pass on their genes for beak type.