#: ___ Scientist’s Name: _____________________
Competency 5 - Demonstrate an understanding of the
molecular basis of heredity.
a. Analyze and explain the molecular basis of heredity and the
inheritance of traits to successive generations by using the
Central Dogma of Molecular Biology. (DOK 3)
 Structures of DNA and RNA
 Processes of replication, transcription, and translation
 Messenger RNA codon charts
Chapter 12–1, 12-2, & 12-3 (Textbook)
Section 10 (DaBook)
Mendelian Genetics
PowerPoint Questions
Gregor Mendel
1. Who is responsible for our laws of inheritance?
2. What organism did Mendel study?
3. When was Mendel's work recognized?
4. When did Mendel perform his experiments & how many plants did he grow?
5. What did Mendel notice about offspring traits?
6. How is Mendel referred to today?
7. In what country did Mendel do his research on peas?
8. Mendel stated that physical traits were inherited as _______________.
9. Today we know that particles are actually what?
Terminology
10. Define these three terms:
a. trait b. heredity c. genetics 11. Name & describe two types of genetic crosses.
12. What is used to solve genetic crosses?
13. Sketch a Punnett square & show how they are used to solve a genetics problems.
14. Use a Punnett square to solve a cross between two parents that both have the
genotype Yy.
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15. What are alleles & what are the two forms?
16. Explain the difference between dominant & recessive alleles.
17. Using a letter of the alphabet, show how each allele would be represented.
18. What is a genotype and write 3 possible genotypes?
19. What is a phenotype and write possible phenotypes for your genotypes in
question 18?
20. Using these alleles, R = red flower and r = yellow flowers, write all possible
genotypes & phenotypes.
21. What are homozygous genotypes?
22. Write a homozygous dominant genotype.
23. Write a homozygous recessive genotype.
24. What is meant by a heterozygous genotype?
25. Write a heterozygous genotype.
26. Heterozygous genotypes are also called _____________.
27. What two things actually determine an organism's characteristics?
Pea Experiments
28. Give 4 reasons that Mendel used garden peas, Pisum sativum, for his
experiments.
29. Name the male and female parts of a flowering plant and explain how
pollination occurs.
30. What is the difference between self and cross pollination?
31. Explain how Mendel cross pollinated his pea plants.
32. How did Mendel get pure plants?
33. Name 8 pea plant traits and give the dominant & recessive form of each.
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34. How did Mendel's experimental results compare to the theoretical genotypic
ratios? Explain.
35. What does P1 mean?
36. What is the F1 generation?
37. What is the F2 generation?
38. What results from this cross --- TT x tt?
39. What results do you get from crossing two hybrids (Tt x Tt)?
40. Show all your work for solving a P1 monohybrid cross for seed shape.
Trait:
Alleles:
P1 cross: __________ x __________
Genotype ____________
Phenotype ___________
G. Ratio _____________
P. Ratio _____________
41. The offspring of the above cross are called the _____ generation.
42. Show all your work for solving a F1 monohybrid cross for seed shape.
Trait:
Alleles:
F1 cross: __________ x __________
Genotype ____________
Phenotype ___________
G. Ratio _____________
P. Ratio _____________
43. Show all your work for solving both F2 monohybrid crosses for seed shape.
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Trait:
Alleles:
F2 cross: ________ x ________ F2 cross: ________ x ________
Genotype ____________
Phenotype ___________
G. Ratio _____________
P. Ratio _____________
Genotype ____________
Phenotype ___________
G. Ratio _____________
P. Ratio _____________
Mendel's Laws
44. _________ are responsible for inherited traits.
45. Phenotype is based on _______________.
46. Each trait requires _____ genes, one from each ____________.
47. State the Law of Dominance and give an example.
48. State the Law of Segregation and tell when alleles are "recombined".
49. State the Law of Independent assortment & tell what type of crosses show this.
50. Using the formula 2n where n = the number of heterozygotes, tell how many
gametes will be produced by each of the following allele combinations:
a. RrYy
b. AaBbCCDd
c. MmNnOoPPQQRrssTtQq
51. What are the possible allele combinations in the egg and sperm from the
following cross --- RrYy x RrYy.
52. Show how to work an F1 dihybrid cross for seed shape & seed color.
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Traits:
Alleles:
F1 cross __________ x __________
GR
Genotypes
PR
Phenotypes
53. Complete this cross or crosses for eye color & curliness of the hair --- bbC__ x
bbcc.
54. Draw a table summarizing Mendel's 3 laws.
Incomplete and Co-Dominance
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55. Incomplete dominance occurs in __________ and produces a phenotype
_______________ the phenotype of the two parents.
56. Show your work solving a cross for flower color in snapdragons when there is
incomplete dominance.
Trait:
Alleles:
Cross: RR x rr
Genotype ____________
Phenotype ___________
G. Ratio _____________
P. Ratio _____________
57. What is codominance & give an example?
58. Write the genotypes for each of these blood types:
type A
type B
type AB
type O
59. Solve this codominance problem: IBIB x IAi.
60. Solve this codominance problem for blood type: ii x IAIB.
Sex-Linked Traits
61. What are sex-linked traits?
62. Name the sex chromosomes.
63. Write the genotype for male and for female.
64. Most sex-linked traits are carried on what chromosome?
65. Give an example of a sex-linked trait in fruit flies.
66. Show the results of crossing a red-eyed male (XRY) with a white-eyed female
(XrXr) fruit fly.
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RR =
Rr =
rr =
XY =
XX =
Cross:
__________ x __________
Genotype ____________
Phenotype ___________
G. Ratio _____________
P. Ratio _____________
67. What is meant by a female carrier?
68. Name a disease that can be carried in this manner.
1. Read your mRNA codon 
ACU
st
nd
2. Find 1 base on the left, 2 base on the top, 3rd base on the right. Find
where they all cross in the chart.
3. ReadDifferent
your amino
acid. code
for different
Threonine
codons
amino acids!!!
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Label the two types of nucleotides based on rings.
messenger-RNA
transfer-RNA
ribosomal-RNA
___________________ Carries the DNA code from nucleus to cytoplasm
___________________ Made by the nucleolus
___________________ Adds the correct amino acid to the growing protein chain
___________________ Combines with proteins to form ribosomes
___________________ Has a CODON region
___________________ Has an ANTICODON region
___________________
___________________
___________________
COMPARE AND CONTRAST
CHROMATIN
CHROMOSOMES
DNA
RNA
What are DNA/proteins doing?
Type of cell seen in?
COMPARE AND CONTRAST
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Double / Single stranded?
Sugar used?
List all nitrogen bases it has
Which nitrogen base is missing?
Location in cell?
USE THE mRNA CODE WHEEL to
tell the amino acid sequence coded
for by the following message:
UCA AAA UUC
Name the parts/structures of a cell:
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A = __________________
B = __________________
C = __________________
D = __________________
E = __________________
F = __________________
NAME THIS KIND OF RNA.
Name the molecule attached at the arrow.
Nucleic Acids
DNA - The Double Helix
Recall that the nucleus is a small spherical, dense body in a cell. It is often called the "control
center" because it controls all the activities of the cell including cell reproduction, and heredity.
Chromosomes are microscopic, threadlike strands composed of the chemical DNA (short for
deoxyribonucleic acid). In simple terms, DNA controls the production of proteins within the cell.
These proteins in turn, form the structural units of cells and control all chemical processes within the
cell. Think of proteins as the building blocks for an organism, proteins make up your skin, your
hair, and parts of individual cells. The proteins that are made largely determine how you look. The
proteins that will be made for your body are determined by the sequence of DNA in the nucleus.
What important polymer is located in the nucleus? _______________
___________ is the instructions for making a cell's ______________.
Chromosomes are composed of genes, which is a segment of DNA that codes for a particular
protein, which in turn codes for a trait. Hence you hear it commonly referred to as the gene for
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baldness or the gene for blue eyes. Meanwhile, DNA is the chemical in which genes and
chromosomes are made. DNA is called a nucleic acid because it was first found in the nucleus. We
now know that DNA is also found in some organelles such as the mitochondria and chloroplasts. It
is the DNA in the nucleus that actually controls the cell's workings.
_______ on chromosomes code for specific ___________ in a cell.
DNA is also found in _____________ and ____________.
In 1953, James Watson and Francis Crick established the structure of DNA. The shape of
DNA is a double helix, which is like a twisted ladder. The sides of the ladder are made of
alternating sugar and phosphate molecules. The sugar is a pentose called deoxyribose. Color all the
phosphates pink (one is labeled with a "p"). Color all the deoxyribose sugars blue (one is labeled
with a "D").
What is meant by a double helix? ____________________________
Who was Rosalind Franklin?
Name a pentose sugar. _________________
The sides of DNA are made of _____________ and ______________.
The rungs of the ladder are pairs of 4 types of nitrogen bases. The bases are known by their
coded letters --- A, G, T, and C. These bases always bond in a certain way. Adenine will only bond
to thymine. Guanine will only bond with cytosine. This is known as the "Base-Pair Rule." The
bases can occur in any order along a strand of DNA. The order of these bases is the code that
contains the instructions. For instance, ATGCACATA would code for a different gene than
AATTACGGA. A strand of DNA contains millions of bases. (For simplicity, the image only contains
a few.)
What makes up the "rungs" of DNA? ____________________
What will pair with adenine? _____________
Color the thymines orange.
Color the adenines green.
Color the guanines purple.
Color the cytosines yellow.
***Note that that the bases attach to the sides of the ladder at the sugars and not the phosphate.
The DNA helix is actually made of repeating units called nucleotides. Each nucleotide consists
of three molecules: a sugar (deoxyribose), a phosphate, which links the sugars together, and then
one of the four bases. Two of the bases are purines - adenine and guanine. The pyrimidines are
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thymine and cytosine. Note that the pyrimidines are single ringed and the purines are double
ringed. Color the nucleotides using the same colors as you colored them in the double helix.
Nucleotides are made of a pentose ___________, a ____________, and a nitrogencontaining __________.
Name 2 bases with double C-N rings. ____________________
The two sides of the DNA ladder are held together loosely by hydrogen bonds. The DNA
can actually "unzip" when it needs to replicate - or make a copy of itself. DNA needs to copy itself
when a cell divides, so that the new cells each contain a copy of the DNA. Without these
instructions, the new cells wouldn't have the correct information. The hydrogen bonds are
represented by small circles. Color the hydrogen bonds grey.
____________ bonds between bases must be broken to copy DNA.
Copying DNA to make two, identical DNA molecule is called ____________.
Messenger RNA
So, now, we know the nucleus controls the cell's activities through the chemical DNA, but
how? It is the sequence of bases that determine which protein is to be made. The sequence is like a
code that we can now interpret. The sequence determines which proteins are made and the
proteins determine which activities will be performed. This is how the nucleus is the control center
of the cell. The only problem is that the DNA is too big to go through the nuclear pores so a
chemical is used to read the DNA in the nucleus. That chemical is messenger RNA (mRNA). The
messenger RNA (mRNA) is small enough to go through the nuclear pores. It takes the "message" of
the DNA to the ribosomes and "tells them" what proteins are to be made. Recall that proteins are
the body's building blocks. Imagine that the code taken to the ribosomes is telling the ribosome
what is needed - like a recipe.
Messenger RNA is similar to DNA, except that it is a single strand, and it has NO thymine. Instead
of thymine, mRNA contains the base Uracil. In addition to that difference, mRNA has the sugar
ribose instead of deoxyribose. RNA stands for Ribonucleic Acid. Color the mRNA as you did the
DNA, except Color the ribose a DARKER BLUE, and the uracil brown.
mRNA has a ____________ strand of nucleotides.
__________ replaces __________ on RNA.
_________ is the pentose sugar on RNA.
__________, not DNA can leave the nucleus through ________ in the nuclear envelope.
Proteins are made at the _____________.
The Blueprint of Life
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Every cell in your body has the same "blueprint" or the same DNA. Like the blueprints of a
house tell the builders how to construct a house, the cellular DNA "blueprint" tells the cell how to
build the organism. Yet, how can a heart be so different from a brain if all the cells contain the
same instructions? Although much work remains in genetics, it has become apparent that a cell has
the ability to turn off most genes and only work with the genes necessary to do a job. We also
know that a lot of DNA apparently is nonsense and codes for nothing. These regions of DNA that
do not code for proteins are called "introns," or sometimes "junk DNA.” The sections of DNA that
do actually code for proteins are called "exons."
__________ are non-coding segments of DNA.
DNA Molecule
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