2. Explain why Drosophila melanogaster is a good experimental organism for genetic studies.
3. Explain why linked genes do not assort independently.
4. Distinguish between parental and recombinant phenotypes.
5. Explain how crossing over can unlink genes.
6. Explain how Sturtevant created linkage maps.
7. Define a map unit.
8. Explain why Mendel did not find linkage between seed color and flower color, despite the fact that these genes are on the same chromosome.
9. Explain how genetic maps are constructed for genes located far apart on a chromosome.
10. Explain the effect of multiple crossovers between loci.
11. Explain what additional information cytogenetic maps provide.
Sex Chromosomes
12. Describe how sex is genetically determined in humans and explain the significance of the SRY gene.
13. Distinguish between linked genes and sex-linked genes.
14. Explain why sex-linked diseases are more common in human males.
15. Describe the inheritance patterns and symptoms of color blindness, Duchenne muscular dystrophy, and hemophilia.
16. Describe the process of X inactivation in female mammals. Explain how this phenomenon produces the tortoiseshell coloration in cats.
Errors and Exceptions in Chromosomal Inheritance
17. Explain how nondisjunction can lead to aneuploidy.
18. Define trisomy, triploidy, and polyploidy. Explain how these major chromosomal changes occur and describe possible consequences.
19. Distinguish among deletions, duplications, inversions, and translocations.
20. Describe the type of chromosomal alterations responsible for the following human disorders: Down syndrome, Klinefelter syndrome, extra Y, triple-X syndrome, Turner syndrome, cri du chat syndrome, and chronic myelogenous leukemia.
21. Define genomic imprinting. Describe the evidence that suggests that the Igf2 gene is maternally imprinted.
22. Explain why extranuclear genes are not inherited in a Mendelian fashion.
Explain why researchers originally thought protein was the genetic material.
2.
Summarize the experiments performed by the following scientists that provided evidence that DNA is the genetic material:
a. Frederick Griffith
b. Oswald Avery, Maclyn McCarty, and Colin MacLeod
c. Alfred Hershey and Martha Chase
d. Erwin Chargaff
3.
Explain how Watson and Crick deduced the structure of DNA and describe the evidence they used. Explain the significance of the research of Rosalind Franklin.
4.
Describe the structure of DNA. Explain the base-pairing rule and describe its significance.
DNA Replication and Repair
5.
Describe the semiconservative model of replication and the significance of the experiments of Matthew Meselson and Franklin Stahl.
6.
Describe the process of DNA replication, including the role of the origins of replication and replication forks.
7.
Explain the role of DNA polymerases in replication.
8.
Explain what energy source drives the polymerization of DNA.
9.
Define antiparallel and explain why continuous synthesis of both DNA strands is not possible.
10.
Distinguish between the leading strand and the lagging strand.
11.
Explain how the lagging strand is synthesized even though DNA polymerase can add nucleotides only to the 39 end. Describe the significance of Okazaki fragments.
12.
Explain the roles of DNA ligase, primer, primase, helicase, topoisomerase, and single-strand binding proteins.
13.
Explain why an analogy can be made comparing DNA replication to a locomotive made of DNA polymerase moving along a railroad track of DNA.
14.
Explain the roles of DNA polymerase, mismatch repair enzymes, and nuclease in DNA proofreading and repair.
First life forms arose on Earth more than 3.5 billion years ago
Single-celled, microscopic organisms (living thing) appeared first & floated alone in seas
Over 40 million species (types of organisms) exist with only about 2 million identified
Many organisms are unidentified & new species are still discovered
Biology is the study of all living things and how they interact with each other & their environment
Over long periods of time, species changed or evolved so that new species arose from earlier organisms & came to inhabit almost every part of the earth (bacteria living in thermal vents, parasites living inside another organism, etc.)
Organisms must adapt to their specific environment to survive & reproduce
Unifying Themes of Biology
The six unifying themes include:
Cell Structure & Function
Stability & Homeostasis
Reproduction & Inheritance
Evolution
Interdependence of Organisms
Matter, Energy, & Organization
Cell Structure & Function
Cell is the basic unit of structure & function
All organisms are made of one or more cells; Unicellular (one celled) or Multicellular (Composed of more than one cell)
UNICELLULAR AMOEBA
Cells are small but highly organized; they contain specialized structures that carry out the jobs of a cell called organelles
CELLULAR ORGANELLES
There are many different kinds of cells, but all cells have similarities
All cells are surrounded by a cell membrane, contain cytoplasm, and have DNA (the genetic information for making new cells or cell structures)
New cells made by unicellular organisms are identical (clones) to the parent cell that produced them – asexual reproduction
Multicellular organisms begin life as one fertilized cell (sexual reproduction), but the cells multiplied and underwent differentiation (changed structure & function) to become many different kinds of cells
Stability & Homeostasis
All organisms maintain stable internal conditions such as body temperature & water content
Stable level of internal conditions called homeostasis
Reproduction & Inheritance
All organisms reproduce new organisms like themselves by transmitting hereditary material to their offspring
DNA (Deoxyribonucleic acid) is a large molecule containing the hereditary material of the cell
DNA MODEL
In unicellular organisms like bacteria, DNA exists as a single loop or chromosome in the cytoplasm
BACTERIA
In multicellular organisms, DNA is enclosed in a membrane known as the nucleus
Genes are short segments of DNA the carry the instructions for a single trait of an organism
DNA of a cell contains all of the genes (instructions) it will ever need
All body cells have a complete set of DNA (genome), but different types of cells use certain genes from the set; example: Muscle cells have the genes to make thyroxine, but they don’t use these genes
In sexual reproduction, an egg (ovum) is fertilized by a sperm to form a zygote so the new organism is made of cells with hereditary information from both parents
In asexual reproduction, cells copy their DNA & split so all new cells are identical
Evolution
Populations of organisms change over time or evolve (Theory of Evolution)
DARWIN – THEORY OF EVOLUTION
Natural selection or “survival of the fittest” is the process that drives evolution
Organisms with favorable traits are better able to survive & reproduce
The survival of organisms with favorable traits causes a gradual change in populations of organisms over many generations
Evolution by natural selection is driven by competition for resources such as food, habitat, mates
Interdependence of Organisms
Ecology is the study of the interaction of organisms with each other and their environment
Sunlight is the ultimate energy for all organisms
Energy from the sun is passed from one organism to another; producers (plants) to herbivore (plant eater) to carnivore (meat eater) to decomposers (break down dead organisms)
ENERGY FLOW IN A FOOD CHAIN
Abiotic (nonliving factors) such as air, water, energy, soil, temperature, & minerals are also needed for survival
Biotic factors include all living things on earth (plants, animals, fungi, microorganisms)
Biosphere supports life & includes the biotic (all organisms) & the abiotic (all nonliving factors) on earth
Organisms respond to their environment by:
* Fleeing
* Adapting
* Dying
Most organisms can survive a temporary change, but permanent change can lead to extinction (dinosaurs)
Thousands of species are listed endangered (population so small could become extinct)
Human interference is the main cause for endangerment & extinction
* Pollution of land, air, and water
*Hunting for sport, food, and commercial products also threatens the survival of many organisms
* Clear-cutting rain forests
* Diverting rivers & lakes
* Draining wetlands (everglades)
*Global Warming
Endangered organisms can be protected & returned to larger population size (American Bison almost wiped out –60 million to 250 in 90 years- now several thousand herds)
AMERICAN BISON
Species is a group of organisms so similar to one another that they can interbreed & produce fertile offspring
Extinction of any species upsets the balance of nature (Almost extinct Pacific Yew tree found to contain chemical used to treat cancer)
PACIFIC YEW TREE
Matter, Energy, & Organization
Organisms are highly organized, maintain internal order, & require a constant energy supply
Plants & unicellular organisms with chlorophyll capture sunlight through photosynthesis & store it in food to be used by other organisms
Autotrophs or producers use sunlight, water, & carbon dioxide to make glucose (energy rich sugar) & oxygen – photosynthesis
Heterotrophs (consumers) feed on producers or other consumers to get energy & release carbon dioxide
Biology affects life in many ways
Biotechnology uses organisms to make products needed by people (human insulin made by bacteria)
Fossils fuels (coal, oil, & natural gas) provide energy & materials such as nylon & polyester
OIL DRILLING
Animal products such as wool, silk, and leather make clothing
Wood provides energy & shelter for us, but endangers other animals (spotted owl) when forests are cut
New medicines, better water treatment & garbage disposal improves our health
Explain why dwarf peas have shorter stems than tall varieties.
2.
Explain the reasoning that led Archibald Garrod to first suggest that genes dictate phenotypes through enzymes.
3.
Describe Beadle and Tatum’s experiments with Neurospora and explain the contribution they made to our understanding of how genes control metabolism.
4.
Distinguish between the “one geneÐone enzyme” hypothesis and the “one geneÐone polypeptide” hypothesis and explain why the original hypothesis was changed.
5.
Explain how RNA differs from DNA.
6.
Briefly explain how information flows from gene to protein.
7.
Distinguish between transcription and translation.
8.
Compare where transcription and translation occur in prokaryotes and in eukaryotes.
9.
Define codon and explain the relationship between the linear sequence of codons on mRNA and the linear sequence of amino acids in a polypeptide.
10.
Explain the early techniques used to identify what amino acids are specified by the triplets UUU, AAA, GGG, and CCC.
11.
Explain why polypeptides begin with methionine when they are synthesized.
12.
Explain what it means to say that the genetic code is redundant and unambiguous.
13.
Explain the significance of the reading frame during translation.
14.
Explain the evolutionary significance of a nearly universal genetic code.
The Synthesis and Processing of RNA
15.
Explain how RNA polymerase recognizes where transcription should begin. Describe the promoter, the terminator, and the transcription unit.
16.
Explain the general process of transcription, including the three major steps of initiation, elongation, and termination.
17.
Explain how RNA is modified after transcription in eukaryotic cells.
18.
Define and explain the role of ribozyme.
19.
Describe the functional and evolutionary significance of introns.
The Synthesis of Protein
20.
Describe the structure and functions of tRNA.
21.
Explain the significance of wobble.
22.
Explain how tRNA is joined to the appropriate amino acid.
23.
Describe the structure and functions of ribosomes.
24.
Describe the process of translation (including initiation, elongation, and termination) and explain which enzymes, protein factors, and energy sources are needed for each stage.
25.
Describe the significance of polyribosomes.
26.
Explain what determines the primary structure of a protein and describe how a polypeptide must be modified before it becomes fully functional.
27.
Describe what determines whether a ribosome will be free in the cytosol or attached to the rough endoplasmic reticulum.
28.
Describe two properties of RNA that allow it to perform so many different functions.
29.
Compare protein synthesis in prokaryotes and in eukaryotes.
30.
Define point mutations. Distinguish between base-pair substitutions and base-pair insertions. Give examples of each and note the significance of such changes.
31.
Describe several examples of mutagens and explain how they cause mutations.
32.
Describe the historical evolution of the concept of a gene.
Indicate whether the sentence or statement is true or false.
1.
When a tRNA anticodon binds to an mRNA codon, the amino acid detaches from the tRNA molecule and attaches to the end of a growing protein chain.
2.
Only ribosomal RNA plays a role in translation.
3.
During DNA replication, the molecule unzips and the exposed DNA nucleotides pair with other
specific nucleotides present in the nucleus
4.
Humans pass exact copies of their DNA to their offspring.
5.
Watson and Crick proposed a model of DNA
6.
Amino acids are linked together by hydrogen bonds.
7.
During transcription, the information on a DNA molecule is “rewritten” into an mRNA molecule.
8.
All codons encode amino acids.
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
9.
Purines and pyrimidines are
a.
bases found in amino acids.
b.
able to replace phosphate groups from defective DNA.
c.
names of specific types of DNA molecules.
d.
bases found in nucleotides.
10.
Chargaff’s rules, or the base-pairing rules, state that in DNA
a.
the amount of adenine equals the amount of thymine.
b.
the amount of guanine equals the amount of cytosine.
c.
the amount of guanine equals the amount of thymine.
d.
Both a and b
11.
ATTG : TAAC ::
a.
AAAT : TTTG
c.
GTCC : CAGG
b.
TCGG : AGAT
d.
CGAA : TGCG
12.
Which of the following types of RNA carries instructions for making proteins?
a.
mRNA
c.
tRNA
b.
rRNA
d.
All of the above
13.
Which of the following is not found in DNA?
a.
adenine
c.
uracil
b.
cytosine
d.
None of the above
14.
Suppose that you are given a polypeptide sequence containing the following sequence of amino acids: tyrosine, proline, aspartic acid, isoleucine, and cysteine. Use the portion of the genetic code given in the table below to determine the DNA sequence that codes for this polypeptide sequence.
mRNA
Amino acid
UAU, UAC
tyrosine
CCU, CCC, CCA, CCG
proline
GAU, GAC
aspartic acis
AUU, AUC, AUA
isoleucine
UGU, UGC
cysteine
a.
AUGGGUCUAUAUACG
c.
GCAAACTCGCGCGTA
b.
ATGGGTCTATATACG
d.
ATAGGGCTTTAAACA
15.
In order for protein synthesis to occur, mRNA must migrate to the
a.
ribosomes.
c.
RNA polymerase.
b.
lac operon.
d.
heterochromatin.
16.
After the primary structure of a protein has been completed
a.
the codons and anticodons unite.
b.
an enzyme attaches adjacent amino acids to each other to form a chain.
c.
the protein folds into the secondary and tertiary structures.
d.
the tRNA molecules remain attached until the protein is secreted from the cell.
17.
Which of the following is not part of a molecule of DNA?
a.
deoxyribose
c.
phosphate
b.
nitrogenous base
d.
ribose
18.
During replication in a molecule of DNA, one separation likely to occur is between
a.
cytosine and guanine
c.
ribose and adenine
b.
phosphate and deoxyribose
d.
uracil and thymine
19.
A gene may be described as
a.
a sequence of amino acids.
b.
special proteins found in chromosomes.
c.
a sequence of nucleotides that controls the production of a certain protein.
d.
a sequence of nucleotides coding for the production of starches and sugars.
20.
The synthesis of a new double strand of DNA begins when the two strand of the original DNA helix
a.
‘unzip’.
c.
attract nitrogenous bases.
b.
act as a template.
d.
destroy a genetic code.
21.
Genes(DNA) affect cell structure and function by directing the synthesis of
a.
nucleic acids
c.
nucleotides
b.
hereditary traits
d.
proteins
22.
Protein molecules are made up of
a.
fats
c.
lipids
b.
nucleotides
d.
amino acids
23.
During, DNA replication, DNA
a.
converts to RNA
c.
joins mRNA
b.
joins tRNA
d.
strands separate
24.
Which is not true about proteins?
a.
They control biochemical pathways within the cell.
b.
They direct the synthesis of lipids.
c.
They are composed of sugars.
d.
They take responsibility for cell movement.
25.
Molecules of DNA are composed of long chains of
a.
amino acids.
c.
monosaccharides.
b.
fatty acids.
d.
nucleotides.
26.
Watson and Crick were the first scientists to state that DNA
a.
contains phosphate groups
c.
has four nitrogen bases
b.
undergoes transcription
d.
has a double helix shape
27.
The two chains of a DNA molecule are connected by
a.
nitrogen bonds
c.
bases
b.
relatively weak chemical bonds
d.
nucleotides
28.
All nucleotide molecules contain the same kind of
a.
ribose sugar
c.
pyrimidine
b.
purine
d.
phosphate group
29.
After DNA replication, the two DNA molecules that are made
a.
are complementary.
c.
must replicate again.
b.
are identical.
d.
cannot replicate again.
30.
Sixty-four codons for 20 amino acids requires that
a.
some amino acids lack codons
b.
some amino acids have more than one codon
c.
all amino acids have two codons
d.
none of the above
31.
Which of the following combines with amino acids
a.
DNA
c.
tRNA
b.
mRNA
d.
B and C
32.
rRNA has a function in
a.
synthesizing DNA.
c.
forming ribosomes.
b.
synthesizing mRNA.
d.
transferring amino acids to ribosomes.
33.
The DNA code consists of sequences of nucleotides arranged in groups of
a.
variable number
c.
threes
b.
twos
d.
fours
34.
Unlike mRNA, the DNA molecule is
a.
double-stranded
c.
like a ladder
b.
single-stranded
d.
both A and C
35.
The number of bases in a row in a gene that codes a protein composed of 200 amino acids is
a.
200
c.
600
b.
400
d.
800
36.
A DNA molecule unzips during
a.
replication
c.
translation
b.
transcription
d.
both A and B
37.
A DNA chain has the following sequence of bases, TAG. The corresponding messenger RNA
chain should have the sequence
a.
ATC
c.
ATG
b.
UTC
d.
AUC
38.
Unlike DNA, RNA
a.
contains deoxyribose.
c.
contains thymine.
b.
is double stranded.
d.
contains uracil.
39.
Which molecule contains deoxyribose
a.
DNA
c.
tRNA
b.
mRNA
d.
both B and C
40.
Each combination of three nitrogenous bases on messenger RNA forms a (an)
a.
anticodon.
c.
enzyme.
b.
codon.
d.
nuclei acid.
41.
In RNA, uracil is complementary to:
a.
guanine
c.
thymine
b.
adenine
d.
cytosine
42.
Once a molecule of transfer RNA has released its amino acid, the tRNA
a.
becomes attached to messenger RNA.
b.
becomes attached to ribosomal RNA.
c.
is destroyed as an individual molecule.
d.
moves away to pick up another amino acid.
43.
If the sequence of bases in a segment of a DNA strand were cytosine, guanine, adenine, thymine, adenine, then the sequence in a complimentary strand of newly-made mRNA would be
