Download Study Guide – Unit 4: Genetics

Study Guide – Unit 4: Genetics
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Genetics
DNA
Transcription & Translation
Genetic Disorders & Technology
Genetic Engineering
Vocabulary:
allele, dominant allele, recessive allele, genotype, heterozygous,
homozygous, phenotype, law of segregation, law of independent assortment,
monohybrid cross, dihybrid cross, codon, anticodon, transcription,
translation, rRNA, tRNA, mRNA, sex-linked disorders, single-gene
disorders, induced mutation, spontaneous mutation, genetic engineering,
transgenic, autosomal dominant disorder, autosomal recessive disorder,
chromosomal abnormalities
*Add in aneuploidy, monosomy, nondisjunction, trisomy from Unit 3
1. Circle the letter of each sentence that is true about alleles.
a. Recessive alleles are never present when dominant alleles
are present.
b. Alleles are different forms of a gene.
c. A trait controlled by a dominant allele always shows up in
the organism when the allele is present.
d. Recessive alleles hide dominant alleles.
2. T F Only pea plants that have two recessive alleles for
short stems will be short.
3. Match the pea plant with its combination of alleles.
Pea Plant
Allele Combination
____ purebred short
____ purebred tall
____ hybrid tall
a. two alleles for tall
b. one allele for tall and
one for short
c. two alleles for short
4. A dominant allele is represented by a(n)
___________________ letter. A recessive allele is
represented by a(n) _____________________ letter.
5. How might a geneticist write the alleles to show that a tall pea
plant has one allele for tall and one allele for short?
6. When Mendel crossed two hybrid plants for stem height (Tt)
what results did he always get?
7. Mendel used the term ____________________- to
describe heterozygous pea plants.
8. T F In codominance, the alleles are neither dominant nor
recessive.
9. What are the four nitrogen bases that make up a DNA
molecule?
10. Circle the letter of each sentence that is true about genes,
chromosomes, and proteins.
a. Genes control the production of proteins in an organism’s
cells.
b. Proteins help determine the size, shape and other traits of an
organism.
c. Chromosomes are made up mostly of proteins.
d. A single gene on a chromosome contains only one pair of
nitrogen bases.
11. One group of three nitrogen bases codes for one
_________________.
12. During protein synthesis, the cell uses information from a
_____________________ on a chromosome to produce a
specific _____________________.
13. Proteins are made on ___________________ in the
cytoplasm of the cell.
14. State two differences between DNA and RNA.
15. List the two kinds of RNA and describe their job.
16. Circle the letter of the first step in protein synthesis.
a. tRNA carries amino acids to the ribosome.
b. the ribosome releases the completed protein chain
c. mRNA enters the cytoplasm and attaches to a ribosome
d. DNA “unzips” to direct the production of a strand of mRNA
17. Circle the letter of each sentence that is true about
mutations.
a. Cells with mutations will always make normal proteins.
b. Some mutations occur when one nitrogen base is substituted
for another.
c. Some mutations occur when chromosomes don’t separate
correctly during meiosis.
d. Mutations that occur in a body cell can be passed to an
offspring.
18. T F All mutations are harmful.
19. Does transfer RNA perform its function in the nucleus or
cytoplasm? Explain.
31. The total DNA of a cell or of an organism is called its
______________.
20. What is the difference between genotype and phenotype?
32. _______________ are heritable, abrupt changes in the
type, structure, sequence or number of nucleotides of DNA.
21. What is the law of segregation? What is the law of
independent assortment?
33. _________________ are errors that affect only a single
gene (substitutions, insertions or deletions of DNA nucleotides)
22. What are the phenotypes of offspring of a cross between a
homozygous dominant parent and a homozygous recessive
parent if G (green pods) is dominant to g (yellow pods)?
23. Cross a parent that is homozygous dominant for both
characters with a parent that is homozygous recessive for both
characters: Flower color (purple dominant, P and white
recessive, p) and pod color (green dominant, G, and yellow
recessive g)
34. ______________________ produce changes in the
structure of chromosomes (duplications, deletions and
translocation).
35. A ______________________ arises naturally during
DNA assembly (can be caused by toxic chemicals or
substances).
36. What is the most common lethal genetic disease in the US?
37. What disease is caused by a mutation in the hemoglobin
gene?
38. What is the typical cause of Down syndrome?
24. Many characters involve three or more different forms. For
these characters, there exist _____________ alleles.
25. Two alleles for a given character are both fully expressed.
They will equally affect the phenotype of the organism. These
alleles are said to be _________________.
26. Both alleles for a particular trait are partially dominant and
partially expressed (blending), called
________________________.
27. What are two examples of polygenic traits?
28. Genes are made up of sequences with three-base segments
called ______________, which code for unique
__________________.
29. The cell copies the info in a gene making complementary
mRNA strands, called __________________. mRNA strands
are used as the code to assemble amino acids to form protein,
called ____________________.
30. What does the enzyme helicase do? DNA polymerase?
39. What are the most difficult disorders to understand (arising
from environmental factors combined with mutations in multiple
genes)?
40. What is a common method of genetic testing conducting on
an unborn fetus for the presence of some disease-causing
alleles?
41. What is gene therapy?
42. The ____________________ Project is an international
research program aimed at creating a complete map of all the
genes of human beings (20,500 human genes).
43. What is genetic engineering?
Suggestions:
•
Begin studying well in advance! Study in small amounts each night. Do this study guide early!
•
Try to explain concepts to someone else. Write out everything you know on paper.
•
Complete the review questions in the Techbook.
•
Read the unit again!
•
Review labs & ask for help if needed!
•
Watch the relevant videos for the unit on my website under “Flipped Classroom”
•
Study vocab cards! Be able to apply the information.