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Exam 1 Study GuideChapters 1-5
Chapter 1: Introduction to Genetics
I. What is Genetics?a. Study of _________________ and _______________________.
II. Branches of Genetics
Transmission Molecular PopulationTransmission of genes
from generation to generation
Mechanisms underlying storage, replication, and
expression of genes
Explores evolution
Focuses on the ________________
Focuses on the _____________
Focuses on the ____________
III. What is DNA?a. What is it made of? (3 main components).
i. _________________________ii. _________________________
iii. _________________________
b. DNA is a double-stranded nucleic acid polymer. What holds together the strands of nucleotides?
i. ____________________________________ii. How do the bases pair?
1. Adenines (A) base pair with ____________________.2. Guanines (G) base pair with ____________________.
IV. Flow of Genetic Information (Fill in the missing information).a. Write the central dogma:
b. Where is genetic information stored? i. _____________________________________________________
V. What is RNA?a. What are the main differences between DNA and RNA?
i. _______________________________________ii. _______________________________________
iii. _______________________________________
VI. What is a Gene? (Has multiple definitions). a. A gene can be defined as:
Exam 1 Study GuideChapters 1-5
i. A discreet unit of inheritance.ii. A specific DNA region located on a chromosome.
iii. A sequence of nucleotides that encodes information for a functional product.
b. What is a chromosome?i. DNA + proteins = _____________________
ii. How are chromosomes organized in:1. Eukaryotes? ___________________________________
a. Where are they found? ____________________
2. Prokaryotes? __________________________________
a. Where are they found? ____________________
iii. Each gene has a specific location on a chromosome called a __________.
VII. What is an allele?a. One of multiple _____________________ of a gene.
i. Individuals have _____ alleles for each gene. Where does each copy come from?
VIII. Genotype vs. Phenotypea. Genotype is the specific alleles an individual has.b. Phenotype is the individuals’ observable appearance.
i. TIP: Phenotype is the visual expression of genotype!
IX. Terminologya. Homozygote individuals have ________________ alleles for a gene.
i. EX: ______________b. Heterozygote individuals have ___________________ alleles for a gene.
i. EX: ______________
c. Dominant alleles are __________________ in heterozygotes.d. Recessive alleles are _______________________ in heterozygotes. e. Wild-type allele is the most commonly observed phenotype OR genotype.
f. What is the difference between recombination and mutation?i. Most mutations are _______________________.
Exam 1 Study GuideChapters 1-5
Chapter 2: Chromosomes and Cellular Reproduction
I.
II. Prokaryotic Cell Reproductiona. Occurs through a process called ___________________________
i. Steps:1. Copy genetic material2. Separate genetic material3. Cell division
III. Eukaryotic Cell Reproductiona. Mitosis
i. Occurs with ____________________ cells
b. Meiosis i. Occurs with ____________________ cells
***These cells can also undergo mitosis
c. Diploid vs. Haploid i. Diploid cells have ______ copy/copies of each chromosome. ii. Haploid cells have _______ copy/copies of each chromosome.
iii. A pair of chromosomes are called _______________________________ 1. T/F: They carry the same linear sequence of genes.
Prokaryotes Eukaryotes
Exam 1 Study GuideChapters 1-5
IV. Mitotic Cell Cycle
a. Practice problem:i. A cell in G1 has 4 chromosomes (2n = 4).
# of Chromosomes # of DNA moleculesS phase
G2 phaseMetaphaseAnaphase
Cytokinesis (in each daughter cell)
Exam 1 Study GuideChapters 1-5
V. Meiotic Cell Cycle (2 parts)a. Meiosis I
Exam 1 Study GuideChapters 1-5
b. Meiosis II
Exam 1 Study GuideChapters 1-5
c. Practice problem:i. A cell in G1 has 6 chromosomes (2n = 6).
# of Chromosomes # of DNA moleculesS phase
Anaphase ICytokinesis I (each
cell)Anaphase II (each
cell)Cytokinesis II (each
cell)ii.
VI. Sources of Variation in Meiosisa. Recombination
i. Creates __________________________________ of alleles.1. This is due to synapsis and crossing over
ii. How is this different from mutation?
b. Independent Assortmenti. Homologous chromosomes line up randomly at the metaphase plateii. Chromosomes are sorted independently of each other
iii.
1. Possible number of combinations is: _________
Exam 1 Study GuideChapters 1-5
VII. Movement of Sister Chromatids During Mitosisa. Which protein holds together the DNA molecules? ______________
i. Holds together from ______________ to ____________________
b. What protein allows sister chromatids to separate? _______________i. What stage does it act on? _______________
VIII. Movement of Sister Chromatids During Meiosis
a. Meiosis Ii. Which protein holds together the DNA molecules? ______________
1. Where on the chromosome is it acting?a. Homologs: ____________________b. Sister chromatids: ________________________
b. What protein allows sister chromatids to separate? _______________i. In meiosis I, where does it act? _____________________ii. In meosis II, where does it act? _____________________
1. What prevents sister chromatids from separating in meiosis I? a. ___________________________________
c.
Exam 1 Study GuideChapters 1-5
Chapter 3: I. Genotype vs. Phenotype?
a. An organism inherits its __________________b. An organism does not inherit its ___________________________
II. Monohybrid Experiment****a. Follow only ____ characterb. Parents (P) are true breeders, meaning they are __________________________
for a trait.c. F1 offspring express only 1 of the P generation phenotypesd. F2 offspring expresses both P generation phenotypes in a
___________________ ratio.
III. Punnett Squares!a. True breeder, AA x AA
b. True breeder, AA x aa
c. Heterozygote, Aa x Aa
i. Law of segregation: 50% chance of allele A or a passing to any gamete
Exam 1 Study GuideChapters 1-5
IV. What is a backcross?a. Cross F1 genotype with either one of the P parental genotypes (which we know
are truebreeders)
Lets cross F1 (Aa) x P (aa)
1. Genotypic ratio: ______________________2. Phenotypic ratio: _____________________
V. What is a testcross?a. Cross an unknown dominant genotype (AA or Aa?) with a homozygous recessive
genotype
VI. Rules of Probability a. Rule #1: Rule of Multiplication:
i. The probability that 2 or more events will occur together is the product of their individual probabilities
b. Rule #3: Rule of Addition: i. The probability that either 1 or 2 or more mutually exclusive events will
occur is the sum of their individual probabilities
ii. Once mastered, these rules will get you the same results as a Punnett square will!
Exam 1 Study GuideChapters 1-5
VII. Dihybrid Cross***a. Crossed pea plants that differed in 2 characteristicsb. Led to Mendel’s 2nd law: ________________________________________
i. States that alleles at different loci separate independent of one another
c. Crossed two true breeder pea plants F1 progeny had 4 possible combinations of alleles
i. When the F2 generation was crossed, phenotypic ratio of: ____________________________
d. Tip for solving dihybrid crosses:i. Solve them as separate monohybrid crosses! ii. Use the multiplication rule to find the probability of the two crosses
occurring together
e. Let’s practice!i.
1. TIP: look at each gene as a separate monohybrid cross
Exam 1 Study GuideChapters 1-5
ii. BE CAREFUL : make sure you’re paying attention to terminology genotype vs. phenotype
Chapter 4: Sex Determination and Sex-Linked Characteristics:
I. What are the differences between the sexes?a. The gametes produced!
i. Males produce _____________________ gametesii. Females produce ______________________ gametes
II. Why does sexual reproduction exist?a. To form _____________________ different from _______________________
i.
ii. Meiosis produces __________________ gametesiii. Fertilization produces _____________________ gametes
III. What is aneuploidy?a. How does it occur? __________________________________________________
i. What is this called? _________________________________
b. What are the different types of aneuploidy?i. Monosomy: ___________ii. Trisomy: ____________
IV. Types of Aneuploidya. Triplo-X Female
i. How many chromosomes? 1. Genotype: __________________________
Exam 1 Study GuideChapters 1-5
ii. Clinical significance: __________________________________________
b. Kleinfeld’s Syndromei. How many chromosomes?
1. Genotype: __________________________ii. Clinical significance: __________________________________________
c. Turner’s Syndromei. How many chromosomes?
1. Genotype: __________________________ii. Clinical significance: __________________________________________
d. XYY Conditioni. How many chromosomes?
1. Genotype: __________________________ii. Clinical significance: __________________________________________
V. X-chromosome Inactivationa. Why does it occur?b. What is the inactivated chromosome called? ________________________c. What are tortoiseshell cats?
Chapter 5: Extensions and Modifications of Basic Principles
I. What is dominance?a. Dominance affects how genes are _____________________ expressed, not how
they are _______________________inherited
b. Types of dominancei. Complete dominance :
ii. Incomplete dominance:
iii. Co-dominance :
Exam 1 Study GuideChapters 1-5
II. Gene Interactiona. So far, we have assumed that 2 genes at different loci act independently, but
what if they affect each other?i. Ex: dog fur
b. What is epistasis? ___________________________________________________
i. What is an epistatic gene? __________________________ii. What is a hydrostatic gene? _________________________
1. How can we tell the difference?
III. Cytoplasmic Inheritance?a. How many nucleotides do we have in the nuclear genome? _________________b. How many nucleotides do we have in the cytoplasm / mitochondria?
__________________________
i. Which parent passes on mitochondrial DNA?
c. Solving problems:REMEMBER: The phenotype of the offspring is determined by the genotype of the mother
i. PRACTICE:1. A father with the genotype S+S is crossed with a mother that has
the genotype SS. What are the genotypes and phenotypes of the F1 and F2 offspring?