Download DNA Structure, and Function in Cells Quiz 2016 Self

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DNA Structure, and Function in Cells Quiz 2016 Self-Testing Guide ANSWERS in bold.
Students should be able to . . .
Exceptions to Mendel’s Rules of Dominance – remember when we learned about blood type as an exceptions to Mendel’s rule.
1. List the 4 exceptions to Mendel’s dominant overpowers recessive rule of inheritance and give an example of one.
The four exceptions we learned to Mendel’s rule of dominance are: incomplete dominance, Codominance, polygenic dominance and sexlinked dominance.
Incomplete dominance describes when the effect of 2 dominant alleles blends – like when a red flower and a white flower have a pink
offspring.
Codominance explains blood type genotypes. If you receive the type A allele and the type B allele for blood type, you will have AB blood
type because both alleles are dominant to the allele for type O.
Polygenic dominance results when more than one gene contributes to a trait, like the 6 genes that contribute to eye color and the 2 genes
that contribute to hair color.
Sex-linked dominance refers to traits that are located on either the x or y sex chromosomes, like the way red/green color blindness is located
on the x chromosome. Since males only have 1 x, if they inherit the allele for colorblindness there isn’t a second dominant allele to
overpower it.
Pedigree Charts – remember when we used the example of freckles and dimples to track how variations are passed through multiple
generations
2. For the chart shown, where shaded is recessive, what is the genotype of the II4 individual (
(mother in generation II)? Explain how you know.
The II4 individual has a heterozygous genotype. The dominate allele is certain because
the person has a dominant phenotype (because the shape is not shaded). The recessive
allele we know because he has a child that is recessive, proving the he also had a recessive
allele.
3. If you want to find the genotype of a person, which people in the chart should you check to
get information?
When you need to reason through the second allele for anyone who is dominant (because the
shape is not shaded) check the parents and/or offspring. If either has a recessive genotype (shape
is shaded) that’s the only way to be sure the second allele is recessive. Otherwise leave a “?”.
I
d __
d
__
D __
?
__
II
D __
d
__
__
D __
d
D __
d
__
D __
d
__
III
d __
d __
__
D __
?
DNA Structure – remember when we extracted DNA from things like split peas, strawberries, and kiwi fruit. We also played the Twisted Clones
game to build part of a strand of DNA.
4. What is DNA and why is it important?
DNA (deoxyribonucleaic acid) is a large double-helix shaped molecule that carries the code for inherited traits.
5. Where is DNA located in an organism?
DNA is located in the nucleus of nearly all living cells.
6. Which chemical parts of DNA hold the code?
The code that determines the version of an inherited trait for an organism is in the list of nitrogen bases that we call A, T, C, G (adenine,
thymine, cytosine, guanine)
7. Would you expect all DNA, whether from a rose, a turtle, or a ballet dancer to be made from the same phosphate groups, deoxyribose sugar, and the A,T, C,
G nitrogen bases?
All living things are defined by DNA, the sequence of the code (number and order of nitrogen bases) might be different, but all DNA is made
up of an arrangement of the same 4 nitrogen bases.
8. Draw a segment of a DNA molecule that has the code A C C T shown on the left side and show the correct nitrogen bases on the other side. Label the parts
in the long sides, the nitrogen bases, and a nucleotide.
Deoxyribose Sugar
A-T
C-G
Phosphate group
A-T
-T
Nitrogen Base Pair
Nucleotide
C-G
T-A
9. How is DNA related to an allele?
Alleles are different version of a gene, like different versions that create dark hair and the other version that creates light hair. Alleles are
made up of DNA. The DNA is the code to create a specific version of a trait.
DNA Function in Cells – remember when we created a foldable to find the differences between mitosis and meiosis cell division.
10. Describe the 3 components of the cell theory.
The cell theory is defined by three ideas: all living things are made up of cells, new cells can only come from existing cells, and cells are the
smallest functional unit of a living thing.
11. Why do we need new cells?
Growth:
Getting Bigger
Replacement: Replace/repair old/dead cells
Reproduction: Create NEW organism
12. Why does DNA need to duplicate itself?
In order to get more cells, a cell divides. DNA makes a copy of itself so each cell has all the DNA it needs.
13. Describe the 2 processes organisms use to create new cells. Why does an organism need 2 different cell division processes?
Organisms use both mitosis and meiosis to create new cells. Two different process are needed because meiosis creates special cells with one
copy of each chromosome that can be used for reproduction.
14. How many chromosomes will a new human body cell (any cell in the body except a sex cell) contain?
Human body cells contain 46 chromosomes; 23 from mom and 23 from dad.
15. How many chromosomes will a new human sex cell (any cell involved in reproduction) contain?
Human reproductive cells have only 1 copy, so they contain only 23 chromosomes.
16. How is DNA passed on to the offspring in reproduction?
One copy of each chromosome of DNA is contained in the egg and sperm cells. When these 2 cells combine, the new human has 46
chromosomes, 1 copy of each chromosome from each parent and has all the information it needs to grow and live.