1
Q
Describe the cellular organization of genetic material
A
•DNA molecules in a cell are packaged into chromosomes.
•Chromatin is uncondensed complex of DNA.
Chromosomes is condensed chromatin
2
Q
Describe the stages of the cell cycle (G1, S, G2, M/C)
a.Know key events that happen in each stage
A
- G1 phase the cell grows and does normal cell functions
- S phase the cell copies it’s DNA (chromosomes) in preparation. For cell division. Each duplicated chromosome has two sister chromatids
- G2 phase the cell keeps growing produces more organelles in anticipation of cell division.
- Mitosis is the division of the nucleus and the nuclear material.
- Cytokinesis is the physical division of the cytoplasm and its components into two distinct daughter cells
3
Q
Evaluate where a cell spends most of its time in the cell cycle
A
- the cell spends most of its time in interphase
* Metaphase is the longest stage of mitosis
4
Q
Distinguish between
cytokinesis in plant and animal cells
A
- cytokinesis in a plant cel involves the formation of a cell plate, as material for a new cell wall is laid down between two poles of the cell
- Cytokines in an animal cell involves a ring of actin microfilaments which serve as a draw string that pinches the cell around the middle to for a cleavage furrow—shallow groove in cell surface
5
Q
Explain the result of mitosis
A
•produces two genetically identical daughter cells
Stages are prophase, metaphase, anaphase, telophase
6
Q
Explain how offspring acquire genes from parents
A
•through reproductions. either asexual or sexual reproduction.
7
Q
Compare asexual and sexual reproduction
A
- asexual reproduction is one parent that passes copies of all its genes to offspring without fusion of gametes; mitosis in eukaryotes or binary fission in prokaryotes; is genetically identical offspring, or clones; only when there is a mutation is there a variation in the offspring.
- sexual reproduction usually involves two parents which gives rise to genetically unique offspring, regardless of DNA mutations; completed by two cells (gametes) which fuse together to form a single cell called a zygote; the gametes have to have half genetic information so the offspring doesn’t continually grow in genetic information; germ cells go through meiosis do accomplish this half the number of chromosomes.
8
Q
Distinguish between haploid and diploid
A
- (n) haploid is one set (half the number) of chromosomes. a condition when a cell has only one of each kind of chromosome; this never occurs in human cells except for gametes (sperm and egg), which have a haploid number of chromosomes (23)
- (2n) two sets of chromosomes; parental cells have two of every kind of chromosome (one is maternal and the other paternal in origin)-use the expression 2n to denote the two of every kind of chromosome; means the diploid parental number is 46 chromosome (23 from mom and 23 from dad)
9
Q
Distinguish between chromatin, chromosome, chromatid, and homologous chromosomes (homologs)
A
- Chromatin is uncondensed (less condensed) complex of DNA + protein (histones); condenses during cell division; DNA carries hundreds to a few thousand genes
- Chromosomes consist of condensed chromatin; replicated (duplicated) chromosome which is two sister chromatids; attached via centromere- which is a specific DNA sequence where chromatids are attached most closely to one another by protein structure known as kinetochore
- Chromatid is sister chromatid that is joined copies of the original chromosome (one half of a replicated chromosome)
- homologous chromosomes (homologs) is matching chromosomes (one from each parent) that carry genes fro the same type of traits
10
Q
Distinguish between autosomes and sex chromosomes
A
- autosomes are most of the chromosomes contain information that does not determine
- sex chromosomes are a couple of chromosomes (X and Y) contain information that determines gender
11
Q
Explain a karyotype
A
•is the visual display of condensed chromosomes arranged in homologous pairs
12
Q
Distinguish between oogenesis and spermatogenesis
A
- oogenesis is the germ line cells in women only complete the ful meiotic division iIF they are fertilized by the sperm; meiosis in women produces up to four haploid gamets, but only one of them will become a viable egg cell (this assumes that it will be fertilizedx since it does not actually finish meiosis until it is fertilized by a sperm.
- spermatogenesis meiosis in me and produces four haploid gametes which will eventually become four viable sperm.
13
Q
Explain how meiosis reduces the number of chromosomes sets from diploid to haploid
A
•it goes through 2 rounds of meiosis; it reduces the number of homologous pairs on anaphase I then separates those pairs in anaphase II
14
Q
Describe the stages of meiosis
a.Be able to distinguish between events in meiosis I and meiosis II
A
- Prophase I- the nuclear membrane disintegrates; chromatin condenses into chromosomes; spindel forms and connects to chromosomes; synapsis where homologous chromosomes pair up and are connected together through a special protein structure called the synaptonemal complex; crossing over when the homologous chromosomes exchange equivalent peices of their chromosome arms containing alleles and recombinant chromosomes (that carry genes from two different parents)
- Metaphase I- homologous pairs line up on the mataphase plate; pairs randomly line up through independent assortment and helps create new daughter cells with varied collections of chromosomes
- Anaphase I - homologous pairs are separated from each other and moeved to opposite poles; each pole must receive one chromosome from each homologous pair (each chromosome also has a copy or sister chromatid still attached at the kinetochore in the centromere region)
- Telophase I and cytokinesis - two new cells form, each containing a haploid number of chromosomes (each chromosome consists of two sister chromatids through they are no longer identical due to crossing over); cytokinesis is similar to mitosis; chromosomes may or may not decondense and nuclear membrane may or may not reform; no duplication of chromosomes occurs before the next phase
- Prophase II -chromosomes fully condense; nuclear membrane disappears (if it reformed after telophase I); spindle fibers connect to kinetochore on individual sister chromatids
- Metaphas II - chromosomes line up at metaphase plate
- Anaphase II - sister chromatids separate and are pulled to opposite sides of the cell ( at this point they are called daughter chromosomes or unduplicated chromosomes)
- Telophase II and cytokinesis - chromosomes decondense and nuclear membrane reforms; cytokinesis proceeds to divide cytoplasm into two new cells; since meiosis I produced two daughter cells which proceeded into meiosis II, at the end of meiosis II we produce a total of four haploid, genetically unique cells.
15
Q
Compare and contrast mitosis and meiosis
A
- Compare - they both have the phases prophase, metaphase, anaphase, telophase and cytokinesis (even though what happens in the phases are slightly different)
- Mitosis - produces 2 genetically identical daughter cells; produces diploid daughter cells; contains one round of cell division; occurs in somatic cells and unicellular organisms (for asexual reproduction); enables multicellular adult to arise from zygote; produces cells for growth, repair and in some species, asexual reproduction.
- Meiosis - produces 4 genetically unique daughter cells; produces haploid daughter cells; contains two rounds of cell division’ occurs only in germ line cells (for sexual reproduction); produces gametes, reduces number of chromosomes by half and introduces genetic variability among gametes
16
Q
Explain the evolutionary advantage created by meiosis and how it is
created
A
- independent assortment of aleles on different chromosomes during meiosisI ensures genetic diversity in gametes (and offspring)
- crossing over in prophase I ensures genetic diversity in gametes (and offspring)
- random fertilization of sperm and egg ensure diverse combinations of alleles in offspring
17
Q
Distinguish between dominant and recessive, homozygous and heterozygous, true breeding and hybrid, allele and gene, phenotype and genotype
A
- Dominant allele masks or covers up the presence of other alleles; the dominant allele is fully expressed in the phenotype of a heterozygote = what we “see”
- recessive allele is the alleles that are masked; recessive alleles are hidden, we don’t “see” their effect on organisms’s phenotype in a heterozygote only in a homozygous recessive
- homozygous is an organism with two identical alleles for a trait; homozygous dominant or homozygous recessive
- heterozygous is an organism that has two different alleles for a gene; both dominant and recessive for the same gene
- true-breeding is an organism that produces offspring of the same variety over many generations when they self-fertilize; organisms with identical alleles for a paticular trait (PP or pp)
- Hybrid is a mating (crossing) of 2 contrasting true-breeding varieties
- allele is an alternative forms of a gene
- genes discrete regions of DNA on a chromosome that code for specific traits
- phenotype is the physical appearance; description of characteristic/trait
- genotype is the genetic makeup; listing of the 2 alleles; the organism inherits two alleles, one from each parent
18
Q
Describe the standard conventions for describing alleles (ie. Capital and lower case)
A
- use capital letter for a dominant allele
* use lowercase letter for a recessive allele
19
Q
Discuss what organism Mendel used and how he used it to work out the laws of segregation and independent assortment
A
- Mendel discovered the basic principles of heredity by breeding garden peas
- the advantages of pea plants - many varieties with distinct heritable features; short generation time; large number of offspring from each mating; mating can be controlled.
20
Q
State the laws of segregation and independent assortment, and discuss the implications of these laws as they relate to crosses
A
- Laws of segregation - the two alleles of a gene segregate during meiosis and each gamete carries only one allele of each pair; explains the 3:1 ratio of the F2 phenotypes observed monohybrids self-pollinate
- Law of independent assortment - each pair of alleles segregates independently of each other pair of alleles during gamete formation.
21
Q
Describe the P, F1, and F2 generations
A
- P (parental) generation - the true-breeding varieties
- F1 (filial) generation - the hybrid offspring (Pp) of the P generation
- F2 generation - offspring that result when the hybrid offspring of the F1 generation either self-pollinate of cross-pollinate with out F1 hybrids
22
Q
Be able to solve monohybrid or single factor crosses
A
•PPxpp is 100% Pp (using a punnet square)
23
Q
Be able to solve dihybrid or double factor crosses
A
- IE YyRr x YyRr
- make sure to make a allele key, with assigned letters
- punnet square
24
Q
Distinguish between non-linked and linked genes
a. Distinguish between sex linked and linked genes
b. Distinguish between X-linked and Y-linked genes
A
- Linked genes is the genes on the same part of the chromosome. So when the crossing over happens they cross over together
- Non-linked is on different spot or all together different chromosome
- sex linked means the allele is located on the sex chromosomes. Either the X or the Y chromosome.
- X-linked is when it is on the X sex chromosome. Female can be a carrier but she would need two alleles to show on a phenotype while the male only needs one from the mother to show in the phenotype.
- Y-linked genes is only located on the Y sex chromosome and only men can have it and pass it down to their sons.
25
Be able to figure out the different kinds of gametes for a given genotype
•punnet square with mother and father alleles
26
Distinguish between incomplete dominance and codominance
* Incomplete dominance - when heterozygote has a phenotype intermediate between those of the two parents (red flower and white flower makes a pink flower)
* Codominance - condition in which two alleles of a locus are expressed in heterozygote. (reddish and white hare colors are expressed independently of each other so having hair by hair difference)
27
Discuss types of inheritance for a single gene (incomplete dominance, codominance, multiple alleles, and pleiotropy)
* multiple alleles - when 3 or more alleles for a given locus (a gene) exists in a given population (ie blood type)
* pleiotropy - ability of a single gene to have multiple affects on several phenotypic characteristics (ie symptoms of cystic fibrosis)
* Codominance - condition in which two alleles of a locus are expressed in heterozygote.
* Incomplete dominance - when heterozygote has a phenotype intermediate between those of the two parents
28
Discuss types of inheritance for two or more genes (epistasis, polygenic inheritance)
* epistasis - a gene at one locus alters the phenotypic expression of a gene at a second locus, prevention or masking of a phenotype (ie labrador retrievers coat color)
* Polygenic inheritance - alleles at several loci affect a single phenotypic trait expression (ie skin color in humans)
29
Distinguish between the blood types and be able to solve genetic problems
* three alleles for blood type IA, IB, i.
* alleles IAIA or IAIO = genotypes AA or AO = phenotypes Type A
* Allels IBIB or IBIO = genotype BB or BO = phenotype Type B
* Allele IAIB = genotype AB = phenotype type AB
* Allele ii or IOIO = genotype OO = phenotype type O
30
Distinguish between genetic disorder and a genetic condition (know the examples discussed in lecture)
* Genetic conditions is when a recessive inherited condition shows up only in individuals homozygous for the allele (ie albinism)
* Genetic disorder is when the allele change that would affect the ability of a person to survive under normal circumstances and without treatment. (ie tay-sachs disease - dysfunctional enzyme causes an accumulation of lipids in the brain; cystic fibrosis - allele results in defective or absentchloride transport channels in plasma membranse; sickle-cell disease is caused by the substitution of a single amino acid in the hemoglobin protein in red blood cells)
31
Define a carrier
•Carrier is heterozygous individuals who carry the recessive allele but are phenotypically normal
32
Be able to find probabilities
* Multiplication rule - the probability that two or more independent events will occur together is the product of their individual probabilities (ie the probability of homozygous recessive wrinkled pea offspring if both parents are heterozygous round pea)
* Addition rule - the probability that any one of two or more exclusive events will occur is calculated by adding together their individual probabilities (ie probability of heterozygous offspring if both parents are heterozygous round pea)
33
Be able to analyze pedigrees and discuss the inheritance patterns
•pedigree is a chart that shows how a trait and the genes that control it are inherited within a family.
34
Discuss the historical contribution and importance for the following: Fred Griffith, Oswald Avery, Colin MacLeod and Maclyn McCarty, Alfred Hershey and Martha Chase, Erwin Chargaff, Rosalind Franklin, James Watson and Francis Crick
* Fred Griffith and streptococcus pneumonia experiments; inquiry: can a genetic trait be transferred between different bacteria strains?; discovery: transformation (a change in genotype and phenotype due to assimilation of foreign DNA); How this was determined: Griffith mixed heat-killed remains of pathogenic strain with living cells of the harmless strain, some living cells became pathogenic; Conclusion: harmless cells had been transformed into pathogenic cells by an unknown heritable substance
* Oswald Avery, Colin MacLeod and Maclyn McCarty - discovery: DNA was responsible for the transformation observed by Griffith; repeated Griffith experiment with treated pathogenic samples and tested the samples for its ability to trasform live nonpathogenic bacteria; result; only when DNA was left active did transformation occur; the sample that inactivated DNA had only nonpathogenic cells no transformation occurred to form pathogenic strain.
* Alfred Hershey and Martha Chase (the great kitchen blender experiment) - discovery: bacteriophages (viruses that infect bacteria) inject their DNA into bacterial cells; determined by using radioactive sulfur to trace the fate of protein and radioactive phosphorus to trace the fate of DNA; result When proteins were labeled radioactivity remained outside the cells; but when DNA was labeled radioactivity was found inside the cells
* Erwin Chargaff reported that DNA composition varies from one species to the next- in any species the number of A and T bases are equal and the number of G and C bases are equal; base paring rules: A pairs with T and C pairs with G
* Rosalind Franklin crucial contributor to the discovery of DNA's structure - discovery: X-ray diffraction (crystallography) revealed that DNA had repeating units and was therefor helical; she inferred from the patterns that the bases were stacked like rungs of a ladder, and the sugar phosphate backbones were on the outside of the DNA molecule
* James Watson and Francis Crick published material on the physical structure of DNA; using Franklin's model, Watson and Crick put all the pieces together, determine that DNA is a double helix with specific base pairing
35
Explain complimentary base pairing
•Complimentary base pairing is when the A and T pair and C and G pair
36
Explain the characteristics of DNA
* DNA's building blocks is made up of nucleotides
* Nucleotides
* Double helix is antiparellel (3'-5' and 5'-3' on the other side) and complementary (2 strands, each stores the information necessary to reconstruct the other)
37
Indicate the components of a nucleotide
•consist of - 5-C sugar; deoxyribose (backbone--side rails of the ladder); phosphate (backbone--side rails of the ladder); nitrogenous bases (rungs of the ladder): purines (Adenine(A) and Guanine(G)) and pyrimidine (Thymine(T) and Cytosine(C))
38
Distinguish between purines and pyrimidines
* purines have two organic rings Adenine(A) and Guanine(G)
| * pyrimidines have one organic ring Thymine(T) and Cytosine(C)
39
Distinguish between semiconservative, conservative, and dispersive models of DNA replication
* semiconservative model is when a double helix replicates, each daughter molecule will have one old strand (derived or "conserved" from the parent molecule) and one newly made strand
* conservative model is when the two parent strands rejoin
* dispersive model is when each strand is mixed of the old and new.
40
Distinguish between the enzymes involved in DNA replication
* DNA polymerase is the main enzyme involved in the replication of DNA via adding nucleotides
* DNA helicase is the enzymes that untwist the double helix and the replication forks; makes the strands available as template strands
* topoisomerase is the enzymes that break and rejoin the parent DNA ahead of the replication fork relieving the strain caused by unwinding (help keep DNA form "tangling" once unwound)
* primase is the enxyme that synthesizes RNA primer (needed to initiate DNA synthesis)
* DNA polymerase III is the enzymes that synthesis new DNA by adding nucleotides to preexisting chain.
* DNA ligase is the enzyme that joins the sugar phosphate backbones of the Okazaki fragments on the lagging strand
41
Explain how a single strand of DNA is able to serve as a template for the synthesis of another strand
•Since they are complementary and A and T only pair and G and C only pair, one strand can serve as a template to allow for replication since there is one type of combination per letter
42
Explain the results of DNA replication
•When a double helix replicates, each daughter molecule will have one old strand (derived or "conserved" from the parent molecule) and one newly made strand
43
Discuss the flow of genetic information
* DNA
* Transcription in nucleus
* RNA (mRNA)
* Translation ribosomes in cytoplasm
* Protein (polypeptide)
44
Describe the structure and function of the different types of RNA
* mRNA - is the messager RNA that carries a genetic message from the DNA to the protein synthesizing machinery of the cell.
* rRNA is the ribosome RNA used in translation
* tRNA is the RNA that has a triplet anti-codons used in translation to transfer the RNA code to amino acids to create a protein
45
Describe protein synthesis
* Transcription: DNA --> mRNA; in the nucleus
* Transcrition has three stages: initiation - RNA polymerase II separates DNA and joins together RNA nucleotides complementary to the DNA template strand, promoter is recognized at the TATA box and RNA polymerase II binds; elongations - RNA polymerase continues to unwind helix adding RNA nucleotides; termination - transcript is relased upon reaching the polyadenylation signal (AAUAAA) and the RNA polymerase detaches from the DNA
* RNA is the processed with the addition of 5'cap and a poly-A tail; RNA is spliced leaving the exons and the introns stay in the nucleus
* Translation: mRNA --> protein; in the cytoplasm
* Translation components: tRNA with anticodon and polypeptide attached to the other end, ribosomes (consists of protein and rRNA), and requires ATP
* Three steps in translation: initiation - small ribosomal unit binds to mRNA, initiator tRNA with anticodon UAC brings in MET amino acid, large subunit assembles hydrolyzing GTP; elongation - adding amino acids to growing polypetide , codon recognition when tRNA with next anticodon base pair to mRNA enters Asite, peptide bond formation is when GTP used to form peptide bond between amino acids elongating polypetide, and translocation is when the ribosome translocates tRNA in A site to P site, and RNA to p site moved to E site where it is released; termination - ribosome reaches stop codon (UAG, UAA, or UGA) on mRNA and the Asite accepts release protein factor that stimulates hydrolysis of polypetide from tRNA and P site, ribosome assembly dissociates.
46
Be able to diagram the DNA strand, mRNA complement, tRNA complement, or protein (amino acids) for a given sequence
•
47
Where does protein synthesis take place?
* Transcription: DNA --> mRNA; in the nucleus
| * Translation: mRNA --> protein; in the cytoplasm
48
Describe the role ribosomes play in protein synthesis
•the ribosome basically is the place where the mRNA is translated into an amino acid sequence within the cytoplasm
49
Compare and contrast transcription and translation
* the two have the same step of initiation, elongation, and termination
* transcription is the creation of mRNA
* translation is the translation of mRNA into amino acid chain.
50
Explain translocation
•translocation is when the ribosome translocates tRNA in A site to P site, and RNA in P site moved to E site where it is released.
51
Compare and contrast codons and anticodons
* codons are the triplet code on the mRNA that signals for a specific tRNA with an amino acid
* anticodon is the triplet code on the tRNA that is complementary to the codons on the mRNA
* they are both triplet codes, complementary to one another, anti parallel
52
Describe the building blocks of proteins and the type of bond between these building blocks
* polypetide bonds are the bonds that hold the amino acids together.
* amino acids are the building blocks of the proteins
Biology 211
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