BIO 115 Lecture Notes - Lecture 3: Telophase, Prophase, Synaptonemal Complex

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23 Jun 2018

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3. Meiosis

Asexual and Sexual Lifestyles

oOffspring acquire genes from parents by inheritance

oPlants reproduce asexually

oProkaryotes do not reproduce asexually

Genetic Variation

oIndividuals within a population are not genetically identical

Structure of DNA

oDNA double helix is organized as a chromosome in cells

Chromosome- carries genetic info in the form of genes

Eukaryotic- linear (2 ends)

Have multiple chromosomes

Homologous- shared common ancestry, carry same genetic

info

Non-homologous

Prokaryotic- Circular (no end)

One copy from mom/ one copy from dad

1 chromosome

oGenes are the functional unit of DNA

oIndividuals within a species have chromosomes with shared characteristics

Same genes as neighbor but not same variation (alleles)

oAlleles is a variety of a gene

23 pairs of chromosomes/ 46 all

oPloidy

Refer to how many in same cell “type”

Haploid- one copy of each type of chromosome

Diploid- two copies of each type of chromosome

“N” represents the number of types

Polyploidy- multiple sets of chromosomes

Aneuploid- # of sets is not consistent (down syndrome)

oSomatic Cells

All the same in every cell/ types are same

Asexual Reproduction

oOffspring is a “clone” of parent

oNo gametes or fertilization involved

oStill have genetic variation

Mutations: spontaneous & induced

Horizontal Gene transfer from bacteria and viruses

DNA coming from cell ➝ pick up cells form neighbor

Most organisms reproduce asexually: bacteria, yeast, some plants, afid

insects

Sexual Reproduction

oMust involve a union of haploid cells to form a zygote

oPro: greater genetic variability

oCon: specialized cells are energetically expensive; may have to find a mate

Meiosis

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Document Summary

Asexual and sexual lifestyles: offspring acquire genes from parents by inheritance, plants reproduce asexually, prokaryotes do not reproduce asexually. Individuals within a population are not genetically identical. Structure of dna: dna double helix is organized as a chromosome in cells. Chromosome- carries genetic info in the form of genes. Homologous- shared common ancestry, carry same genetic info. One copy from mom/ one copy from dad. 1 chromosome: genes are the functional unit of dna o. Individuals within a species have chromosomes with shared characteristics. Same genes as neighbor but not same variation (alleles: alleles is a variety of a gene. 23 pairs of chromosomes/ 46 all: ploidy. Refer to how many in same cell type . Haploid- one copy of each type of chromosome. Diploid- two copies of each type of chromosome. Aneuploid- # of sets is not consistent (down syndrome: somatic cells. All the same in every cell/ types are same.

Related Questions

1). Thyroid hormone (TH) has been identified as one of the factors promoting phenotype development in the Mexican axolotl salamander. Which of the following statements regarding the impact of TH is FALSE?

A). Axolotls maturing in water with high concentration of TH (thyroxine; T4) metamorphose into a terrestrial form.

B). A genome-wide scan of both the axolotl and its sister species found a large reduction in the number of mRNA transcripts that regulate the production of TH.

C). Adding TH (thyroxine; T4) to the water in which axolotl individuals are reared causes them to remain in a larval stage.

D). Most salamander species produce a burst of TH when they move from water to land.

2).What would be an appropriate evolutionary explanation of the fact that the ordering of some homeotic genes (such as Hox genes) on vertebrate chromosomes parallels the ordering of homeotic genes on fruit fly chromosomes?

A). The similarity is a coincidence, not documented in other invertebrates and largely a result of random mutations.

B). Homeotic genes show that insects and vertebrates are closer relatives than the traditional classification system indicates.

C). Homeotic genes of different animal lineages might be ordered in a similar fashion, yet their sequences are completely different.

D). The similar ordering of homeotic genes in animals, both vertebrate and insect, is due to ancient homology.

3). Which of the following correctly defines "homeotic genes"?

A). Homeotic genes encode proteins that control the cellular environment in a differentiated cell tissue.

B). Homeotic genes are DNA sequences that turn off, but not on, the expression of other genes and are controlled by "master-switch" genes.

C). Homeotic genes are "master-switch" genes that control other genes in a set sequence and thereby affect cell size, shape, division, and the positioning of the cells within the organism.

D). Homeotic genes are DNA sequences that turn on, but not off, the expression of other genes and are controlled by "master-switch" genes.

4). Which of the following is NOT considered a type of heterochrony (change in the rate and timing of development)?

A). hypermorphosis

B). acceleration

C). neoteny

D). ontogeny

5). How does the dominance theory explain why the heterogametic sex is at a disadvantage in Haldane's rule?

A). Beneficial dominant alleles will never be fully expressed in hybrids as they only carry one copy of the sex chromosome that carries the allele.

B). If a dominant allele has a negative effect on the fitness of hybrids, it will always be expressed in the heterogametic hybrids that possess that allele because they only need one copy of the respective sex chromosome.

C). If a recessive allele linked to a sex chromosome has a negative effect on the fitness of hybrids, that allele will always be expressed in the heterogametic hybrids that possess that allele because they only have one copy of the sex chromosome that carries the allele.

D). If a recessive allele linked to a sex chromosome has a positive effect on the fitness of hybrids, that allele will never be expressed in the heterogametic hybrids that possess that allele because they only have one copy of the sex chromosome that carries the allele.

6). In a hypothetical flowering plant species, one population evolves a different response to environmental stimuli and begins to bloom significantly later in the season than nearby populations. What type of reproductive isolating mechanism would this be?

A). hybrid sterility

B). postzygotic

C). prezygotic

D). gametic incompatibility

7). In a study of red spruce trees and black spruce trees, scientists found that the red spruce was living in a smaller geographic area and had much less genetic variation than the black spruce. They proposed that the red spruce might have arisen from a southern population of black spruce, which became geographically isolated from other black spruce populations at some point during the Pleistocene glaciations. What is this an example of?

A). allopatric speciation with the vicariance model

B). sympatric speciation

C). allopatric speciation with the peripheral isolate model

D). sympatric speciation with the ring species model

8). Which of the following defines Haldane's rule and its predictions?

A). If among hybrid offspring one sex is absent, rare, or sterile, that sex is always male.

B). If among hybrid offspring one sex is absent, rare, or sterile, that sex is always female.

C). If among hybrid offspring one sex is absent, rare, or sterile, that sex is heterogametic (has two different sex chromosomes).

D). If among hybrid offspring one sex is absent, rare, or sterile, that sex is homogametic (has two of the same sex chromosomes).

8.) Which of the following statements best explains secondary reinforcement?

A). If the reproductive isolating mechanisms that developed during the geographic isolation are strong but the hybrids have higher fitness than the parent species, then the speciation process will cease.

B). If the reproductive isolating mechanisms that developed during the geographic isolation are somewhat weak but the hybrids between two populations have lower fitness, then the speciation process may continue.

C). If the reproductive isolating mechanisms that developed during the geographic isolation are sufficiently weak as to allow free interbreeding across reunited populations, then the speciation process will halt and a single species will remain.

D). When geographic isolation comes to an end, two populations always complete the divergence process and become separate species.

ceruleanzebra430

Messenger RNA (mRNA)...

a) Is a structural part of a ribosome

b) Brings amino acids to DNA

c) Carries genetic information from the nucleus to the cytoplasm

d) Is a structural part of a chromosome

e) Initiates and directs chemical reactions

Mr. Potato is homozygous dominant (KK), his son, Potato Jr. is heterozygous (Kk). Based on this information, what are the possible genotypes for Mrs. Potato? (Hint: use a Punnet Square).

a) Her genotype is definitely kk

b) Her genotype is either Kk or kk

c) Her genotype is either KK or Kk

d) Her genotype is either KK, or Kk, or kk

e) Mr. Potato cannot be Potato Jrâs biological father

12. Homologous chromosomes:

a) Are members of different chromosome pairs

b) Are genetically identical

c) Carry genetic information that influences the same traits (same genes but probably different alleles)

d) Are only inherited from the mother

e) Are only inherited from the father.

âFitnessâ in an evolutionary sense, refers to an individualâs:

a) Strength

b) Reproductive success

c) Aggressiveness

d) Size

e) Age at death

The fact that individuals who possess favorable traits are more likely to survive and reproduce than those who possess less favorable traits is the basis for the theory of...

a) uniformitarianism.

b) natural selection.

c) the inheritance of acquired characteristics.

d) catastrophism.

e) the fixity of species.

Even with strong selection, genetic variation of a population can be maintained because:

a) Selection only affects one gene at a time.

b) The effects of many alleles are hidden from selection by the effects of other alleles

c) Mutation constantly adds new alleles at an extremely fast rate.

d) Populations always go extinct before their gene frequencies are dramatically altered.

e) Only a and c

Gene Flow is defined as the:
a) Production of new alleles
b) New musical group in which Adam Levine will be the leading vocalist
c) Exchange of genes between populations
d) differential reproductive success of individuals
e) Process by which a DNA base gets extracted out of the nucleus to initiate the process of protein synthesis.

The basic unit of DNA is a molecule called a: a) Nucleotide

b) Base
c) Thymine
d) Prokaryoticcell e) mRNA

How many bases code for one amino acid? a) one

b) two
c) it depends on what amino acid it is d) three
e) four

Hemophilia is a condition that affects: a) more females than males
b) more males than females
c) females and males equally

d) only children born prematurely
e) individuals with a missing portion of chromosome number 5

A clear example of directional selection is:
a) Darwin finches with deeper and thicker beaks associated to a severe drought b) Sickle cell anemia in regions in which Malaria is endemic
c) Achondroplasticdwarfism
d) Fly halteres becoming fully developed wings after modification of a hox gene e) all of the above

Meiosis is evolutionarily significant because:
a) New combination of alleles can arise through independent assortment and crossing over

22.

23.

24.

25.

26.

b) It is the mechanism by which body tissues are repaired
c) It creates somatic cells that are crucial for our body organs to maintain us alive d) It allows forensics to determine the cause of death of unidentified people
e) none of the above

Homologous chromosomes:

a) Are exact copies of each other and contain exactly the same genetic material
b) Are members of different chromosome pairs
c) Are only inherited from the father
d) carry genetic information that influences the same traits (the same genes), however, each of the homologous chromosomes can contain different versions of the same gene (different alleles).

e) carry genetic information that influences different traits because each of the homologous chromosomes contains completely different genes at very different loci

How many chromosome pairs occur in a normal human somatic cell?

a) 46 b) 23 c) 22 d) 24 e) 45

What is the scientific method? Use bullet points to describe the 4 major components.

How is a hypothesis different from a theory?

List the four major components (described during class) necessary for natural selection to occur [AKA Darwinâs Four Postulates] (PDF1-3).

27. Who was Thomas Malthus? In what way(s) Malthus was influential for Darwinâs Theory of Natural Selection? Hint: populations vs resources.

29. What amino acids are being coded for by the gene segment provided below? Nucleotide triplets and their corresponding amino acids are:
ACA= Cysteine; AAA=Phenylalanine; TGG=Threonine; CCT=Glycine; GAT=Leucine; ATA=Tyrosine; AGG=Serine; TCT=Arginine

a) Threonine, serine, glycine, tyrosine, leucine, phenylalanine, arginine, cysteine.

b) Tyrosine, leucine, glycine, threonine, arginine, threonine, serine, cysteine.

c) Arginine, cysteine, serine, glycine, threonine, leucine, phenylalanine, tyrosine.

d) Phenylalanine, leucine, tyrosine, glycine, serine, threonine, cysteine, arginine.

e) Phenylalanine, leucine, tyrosine, glycine, threonine, phenylalanine, arginine, serine.

Expression vectors inprokaryotes do not make functional eukaryotic gene products inbacteria very well because

Answer Not sure which one ?!

		Â· the codon sequence for prokaryotes is differentthan the codon sequence in eukaryotes
		Â· there are no disulfide bridges formed in proteinsnormally made in prokaryotes
		Â· prokaryotic expression vectors cannot translateeukarytic sequences
		Â· eukaryotic genes have introns, and prokaryotesdon't
		Â· eukaryotic genes have exons and prokaryotesdon't

I create a knockout mouseusing the agouti/black fur system \. When I cross the agoutioffspring of the originally engineered mouse, I find a ratio of 2agouti mice to 1 black furred mouse. What is the bestexplanation?

Answer not sure which one?!

		Â· The gene knocked out was recessive.
		Â· The gene knocked out was dominant.
		Â· The gene knocked out was a lethalgene.
		Â· The knockput was integrated into a random spot,and did not knockput the original gene.

A restriction enzyme cuts DNAand leaves the following end

xxCTGCA
xxG

Which of the following could be the sequence of the correspondingend of the other end of the cut DNA?

Answer

Â· xxG
xxCTGCA

Â· xxC
xxGTGCA

Â· xxCCGAT
xxG

Â· xxGGCTA
xxC

An SNP always occurs dueto

Answer

		Â· a one base-pair change.
		Â· a three base-pair change.
		Â· a single restriction site change.
		Â· a single amino acid change.
		Â· None of these.

I PCR out a mutated gene in apatient with Lisenbee chorea (the inability to dance in acoordinated fashion) and I compare it to another patient with thatsame disease phenotype. One subject had a mutation on chromosome 4,and the other subject couldn't rock it because of a mutation onchromosome 5. This is an exampe of

Answer

Â· pleitropy

Â· locus heterogeneity

Â· allelic heterogeneity

Â· dominant negative mutation

Â· penetrance

In his experiments, Mendelnoted that when two traits are involved in a genetic cross, theyare inherited independently of each other. Though Mendel didn'tknow about chromosomes, this still holds true (mostly)because

Answer

		Â· genes on the same chromosome are often mixedthrough meiotic crossover during the formation ofgametes.
		Â· variant alleles of the same gene do not interferewith the phenotypic expression of the gentoype in different geneticloci.
		Â· most higher organisms are diploid, making only twoalleles available for every genetic locus, and there is a 50/50chance of geting either allele from a single parent.
		Â· expression of phenotypes can vary from thegenotypes because of encironmantal influences.
		Â· chromosomes often recombine

Anticipation is caused by amutation that increases in expressivity over subsequentgenerations.

Answer

Â· True

Â· False

Question 44

I have a genotype that shouldproduce a specific phenotype, but some of the individuals with thegenotype do not demonstrate any evidence of the phenotype. I wouldconsider this an example of

Answer

		Â· allelic heterogeneity.
		Â· locus heterogeneity.
		Â· penetrance.
		Â· expressitivity.
		Â· sheer luck.

Question

Which of the following doesnot occur during the PCR reactions?

Answer

		Â· Changes in the reaction temperature by athermocycler
		Â· Denaturation at high temperatures
		Â· Synthesis of oligonucleotide primers
		Â· Extension of primers by DNA polymerase
		Â· Annealing of oligonucleotide primers

Question

DNA markers, or variantnon-coding regions of DNA, are DNA polymorphisms that are usefulfor genetic mapping.

Answer

Â· True

Â· False

A mosaic is an organismwith

Answer

		Â· multiple genotypes within one organism
		Â· multiple alleles within one genotype
		Â· more than one color of fur
		Â· transgenes added to the zygote beforedevelopement
		Â· a wt phenotype but a mutated genotype

Question

Genotype causesphenotype.

Answer

		Â· No, gentoype just influences phenotype.
		Â· Yes, genotype is the DNA sequence that createsphenotype.

Question

A true genetic chimera can becreated by

Answer

		Â· mutating a gene early on in the development of anorganism resulting in different alleles being present in theadult
		Â· multiple fertilized eggs or zygotes fusing to formone embryo
		Â· adding a transgene to the genome of an organismduring fetal development only
		Â· adding cells of a different species to an adultorganism
		Â· adding a transgene to the genome of an animal atany stage in development

Question

The ABO blood group can bestbe explained by the concept of _______.

Answer

		Â· dominant traits
		Â· recessive traits
		Â· allelic heterogeneity
		Â· locus heterogeneity
		Â· vampirism

If a loss of functionmutation creates a dominant phenotype, it may be becauseof

Answer

		Â· haploinsufficiency
		Â· penetrance
		Â· expressivity
		Â· allelic heterogeneity
		Â· locus heterogeneity

Please select the best matchfor each.

Answer

	Â· PCR: Technique used to generatecopies of a DNA fragment
	Â· Southern blot : Screeningprocedure used to assay DNA fragments
	Â· RFLPs : DNA fragments generatedby restriction enzymes that vary in length betweenindividuals
	Â· Northern blot : Screeningprocedure used to assay mRNA fragments
	Â· Electrophoresis Movement ofmacromolecules in an electrical field

Answer

A.	Screening procedure used toassay DNA fragments
B.	Movement ofmacromolecules in an electrical field
C.	Screening procedure used toassay mRNA fragments
D.	DNA fragments generated byrestriction enzymes that vary in length betweenindividuals
E.	Technique used to generatecopies of a DNA fragment

A gene mutates, and theprotein produced has a novel way of interacting with the cell, andcreates a new phenotype because of this new functionality. This iscalled

Answer

		Â· pleitropy
		Â· locus heterogeneity
		Â· allelic heterogeneity
		Â· dominant negative mutation
		Â· gain of function dominant mutation

Question 62

Mutations in the somaticchromosomes may be inherited by the next generation.

Answer

Â· True

Â· False

A degenerate PCR primer withmany variant sequences must be used to make multiple copies of agene

Answer

		Â· if only the protein sequence of the gene productis known to construct the primers
		Â· if the DNA you are using is cDNA to constructthe primers
		Â· if the DNA you are using is genomic DNA to becopied
		Â· if the DNA you are trying to copy iscDNA
		Â· if the vector is prokaryotic and the transformedcell is eukarytotic

Question

Please select the best matchfor each term.

Answer

	Â· Restriction enzyme
	Â· PCR C
	Â· Plasmid
	Â· YAC A
	Â· Dideoxynucleotide

Answer

A.	Endonuclease isolated frombacteria
B.	Eukaryotic cloningvector
C.	Method for amplification ofDNA sequences
D.	Small circular fragment ofDNA
E.	Molecule used in DNAsequencing

Question

A couple goes on MauryPovitch, and the results are in: you are not the father. But noother man impregnated the female (granted, unlikely for a MauryPovitch guest, but work with me here) and he must be the father.DNA analysis claims otherwise, though the child definitely wasmom's (poor thing). What may be going on here?

Answer

		Â· the child is parthenogenic because the motheractually impregnated herself like a shark, and the child's DNA isall mom's
		Â· the child had a mutation that changed the genethat is used to trace paternity
		Â· the child is a mosaic because he is actually a setof twins fused early during fetal development, and therefore camefrom 2 eggs and 2 sperm
		Â· the dad may have germ-line mosaicism, meaning thatthe genotype of his sperm is different from his somaticgenotype
		Â· mitochondrial DNA only comes from mom, so there isno way to tell whobthe baby's father is

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BIO 115 Lecture Notes - Lecture 3: Telophase, Prophase, Synaptonemal Complex

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