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Name: ____________________ Date: ___________ Period______________ Assignment # ________
GENETICS REVIEW
What do your chromosomes tell you?
Directions: Read the paragraph below. Use the vocabulary to help you with words you’re not familiar with. As you work,
answer the questions in the boxes. Then, use the paragraph and the vocabulary to answer the questions on the back.
Your DNA acts like an instruction book for how to build and operate your body. Each of
your nonsex cells has 23 pairs of homologous chromosomes (DNA) in its nucleus. In each
pair, one came from your mother, and the other came from your father.
Each spot on a chromosome gives the
Describe one way someone you know
instructions for a single trait. These spots are
looks like a combination of
called genes. For example, you have several
their mother and father.
genes that tell you what color your eyes are
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going to be. But it’s trickier than that: since
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you have 2 of each chromosome, you have 2
of each gene!
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So, how do your genes figure out their differences? When they both
agree, there’s no problem. If both your
Brown eyes are dominant. If
“freckle” genes said not to have
you have one gene saying to
freckles, you’d know for sure you weren’t going to get freckles. But what if they don’t
have brown eyes, and the other
agree?
saying to have blue eyes, what
Many of your genes are either recessive or dominant. When the two copies of the
color are your eyes?
gene don’t agree, the instructions from the dominant gene are used. For example,
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freckles are recessive. That makes NOT having freckles dominant. So, if one
chromosome says to have freckles, and the other says not to, the person will not have
freckles.
Genetics
Organism
Allele
DNA
Homozygous
Cell
Genetics Vocabulary
Trait
Gene
Recessive Allele
Phenotype
Cell Nucleus
Chromosome
Dominant Allele
Heterozygous
Genotype
1. ______________ = The study of how information is stored in cells and passed on to children.
2. ______________ = A living thing.
3. ______________ = The set of molecules that contain our body’s instruction manual for how to be human. All living
things have this in their cells. It looks like a twisted ladder.
4. ______________ = A characteristic (describing an organism). They are decided by genes from your DNA.
5. ______________ = The smallest unit of living things. Your body is made of millions of these.
6. ______________ = The central part of a cell that contains the cell’s chromosomes.
7. ______________ = long, clumped strand of DNA. Humans have 46 of these in all their body cells.
8. ______________ = A small part of a chromosome that contains the instructions for a specific trait.
9. ______________ = One of the versions of a gene. For example, the gene for freckles has two of these: one that tells you
how to make freckles, and the other that says not to have freckles.
10. ________________________ = The allele that wins when a genotype is heterozygous.
11. ________________________ = The allele that only wins when two are present together.
12. _____________ = The combination of alleles that two chromosomes have for a gene. Represented by two letters!
13. _____________ = Which allele gets used (what the person ACTUALLY looks like).
14. _____________ = When the two alleles agree.
15._____________ = When the two alleles disagree.
Genetics Questions
Directions: Use the definitions and the reading to help answer the questions. They are in order.
1) What is the name of the part of science we are studying? ____________________________________
2) What is another name for a living thing? _________________________________________________
3) Imagine your body has 5 billion cells. How many of each gene does EACH cell have? _____________
4) Plants are alive. Do they have DNA in their cells? _________________________________________
5) Short hair, brown eyes, the ability to roll your tongue, etc, are all examples of ___________________.
6) Are there living things smaller than cells? Why? __________________________________________
7) What is located inside the cell nucleus? _________________________________________________
8) You have 23 pairs of chromosomes. Why are your chromosomes in pairs? _____________________
_________________________________________________________________________________
9) What is a gene? ____________________________________________________________________
10) When there is more than one version of a gene, the versions are called ________________________.
11) If your two chromosomes have different alleles for a gene, does your body use the dominant or the recessive
gene? ____________________________________________________________________
12) Does “F” stand for a dominant or a recessive allele? _______________________________________
13) If I tell you that one chromosome says to have freckles ( f ), and the other says NOT to have freckles ( F ),
have I told you the organism’s genotype or phenotype? __________________________________________
14) If I tell you that the organism has brown hair, is that its genotype or phenotype? _________________
15) If the two genes have matching alleles, it is called _________________________________________.
16) If the two genes don’t have matching alleles, it is called ____________________________________.
Directions: Follow the example. Remember, capital letters are dominant..
“F”= no freckles, “f”=freckles. So, FF = no freckles, Ff=no freckles, and ff=freckles.
17) “B”= brown eyes; “b” = blue eyes. What color are your eyes if your genotype is Bb? ____________
18) “B”=brown hair; “b”=blonde hair. What color is your hair if your genotype is bb? ______________
19) “T”=tongue roller; “t” = can’t roll tongue. If your genotype is TT, can you roll your tongue? ______
20) “C”=curly hair; “c”=straight hair. What is your hair like: CC?_____ Cc? _____ cC? _____ cc?____
21) From question 20, is curly hair or straight hair dominant? Why?______________________________
22) Mr. Soleimani has hazel eyes. Is that his genotype or phenotype? _________________________________