BIOL 1000 Lecture Notes - Lecture 9: Prophase, G0 Phase, Microtubule

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rubycrab690

2 Jul 2018

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University of Manitoba

Department

Biological Sciences

Course

BIOL 1000

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All

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7/2/18

BIOL 1000- MITOSIS AND MEIOSIS

•There are 23 chromosomes from mother and 23 chromosomes from father.

•There are 2 cell types based on chromosome contents: A) Gametes: in which there are 23

dif-

ferent chromosomes that are haploid (n) and include ova (eggs) and sperm. B) Somatic Cells:

which include all cells of the body except cells undergoing or resulting from meiosis; like mus-

cle and nerve cells.

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7/2/18

•There are 46 chromosomes which are diploid (2n); 23 homologous pairs.

•Homologous Chromosomes: a chromosome pair (1 from each parent) that are identical in

length, centromere position and have genes for the same trait like eye colour in the same loca-

tion or locus.

•Gene: it is the unit of heredity and is the region of DNA which contains information for syn-

thesis of proteins, BUT they may have different versions of that trait; like blue eyes (chromo-

some from father) and brown eyes (chromosomes from mother).

•Each somatic cell contains 23 different chromosome pairs. 23 chromosomes form mother

(ovum) which are paired with 23 chromosomes from father (sperm) and that equals 46 chro-

mosomes which are diploid (2n somatic cell).

•The chromosome pairs are numbered from 1-23 and the first 22 pairs are autosomal chromo-

somes or autosomes that contain genes for somatic characteristics like hair and eye colour

and height. The 23rd chromosome contains genes that determine the sex of the child; like

XY from father and XX from mother.

•The somatic ‘parent’ cell (2n) and the genetically identical somatic ‘daughter’ cells (2n). There

are 2 stages to it: Interphase and Mitotic or the cell division phase.

1.1 INTERPHASE: (G1, S AND G2 PHASE):

•Chromosomes present as chromatin. There is normal cellular metabolic activities occurring

like protein synthesis.

•The phases are: A) G1 PHASE: helps in growth and metabolism. At the end of G1 phase the

centromeres replicates.

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7/2/18

•In some cells that do not divide again once mature i.e. they remain in G1 phase in these cells it

is termed as G0 phase; like nerve and some muscle cells.

•B) S PHASE: the chromosomes replicate, but are still present as chromatin which are not indi-

vidually visible. They always occur before the mitotic division. They replicate as ‘sister chro-

matids’ which are attached to each other at an area of DNA called the ‘centromere’. The kine-

tochore proteins (produced during S phase) attach to each centromere to form the kinetochore

(protein and DNA complex).

•A kinetochore is the site of attachment of spindle micro tubules.

• G2 PHASE: it helps in growth, metabolism; the production of enzymes and other proteins

needed for cell division.

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Document Summary

Biol 1000- mitosis and meiosis: there are 23 chromosomes from mother and 23 chromosomes from father, there are 2 cell types based on chromosome contents: A) gametes: in which there are 23 ferent chromosomes that are haploid (n) and include ova (eggs) and sperm. B) somatic cells: which include all cells of the body except cells undergoing or resulting from meiosis; like mus- dif- cle and nerve cells: there are 46 chromosomes which are diploid (2n); 23 homologous pairs. The 23rd chromosome contains genes that determine the sex of the child; like. Xy from father and xx from mother: the somatic parent" cell (2n) and the genetically identical somatic daughter" cells (2n). There are 2 stages to it: interphase and mitotic or the cell division phase. 1. 1 interphase: (g1, s and g2 phase): chromosomes present as chromatin. There is normal cellular metabolic activities occurring like protein synthesis: the phases are: a) g1 phase: helps in growth and metabolism.

Related Questions

23. During meiosis, one way that diversity is achieved is throughthe differential ways maternal and paternal
chromosomes line up at the equator. This phenomenon is knownas:
A. Crossing under; B. Random mating; C. Crossing over; D. Randomshuffling
24. What is the correct order of classification from the leasttraits in common to the most traits in common?
1. Order; 2. Genus; 3. Kingdom; 4. Species; 5. Phylum; 6. Family;7. Class
A. 3,5,1,7,2,6,4; B. 3,7,5,6,1,2,4; C. 3,5,7,6,1,4,2; D.3,5,7,1,6,2,4; E. None of the above 25. Humans are currentlyclassified as Homo sapiens. An earlier human ancestor was Homoerectus. Please
identify the Genus of the earlier human ancestor. A. sapiens; B.Homo; C. Human; D. erectus
26. Whales utilize which type of fertilization? A. Internal; B.External; C. Terrestrial; D. None of the above
27. During internal fertilization, sperm are deposited directlyinto the femaleâs body in order to protect the
gametes. In some female animals, after the sperm fertilizes theeggs, the eggs continue to develop inside the
female, and the developing embryos receive ALL of their nourishmentfrom the mother. These animals are
considered to be: A. Oviparous; B. Viviparous; C. Precocial; D.Ovoviviparous
28. In humans, which gender has separate openings for the urinaryand reproductive systems?
A. Men; B. Women; C. Both A and B; D. None of the above
29. An animalâs anatomical structures can be used to constructphylogenetic trees. What is the term given to the
structures of two animals whereas the structures are very similarbut have different functions? Ex: Forearm of a
human and the wing of a duck:
A. Vestigial Structures; B. Analogous Structures; C. HomologousStructures; D. None of the above
30. Humans have 46 chromosomes in every somatic cell nucleus. Thereare 23 chromosomes from mama and
23 chromosomes from papa. Chromosome #3 from mother and Chromosome#3 from father contain
information to control the same genetic traits. During meiosis 1,duplication of chromosomes results in 2 copies
of chromosome #3 from the father and 2 copies of chromosome #3 fromthe mother. The pair of chromosomes
#3 from the father are refered to as:
A. Sister chromatids; B. Centromeres; C. Homologous chromosomes; D.Spindle apparatus

eringerbil901

What is a genome? What is a genome made of? Describe the bacterial genome. How do bacteria reproduce? What is binary fission? Distinguish between a chromosome and chromatin. Where are chromosomes located in eukaryotic cells? What is the chromosome made of? What is a centromere? What is the centromere's role? What are sister chromatids and how do they arise? Distinguish between somatic cells and germ (gametes) cells. Describe the cell cycle. What are the different phases? What occurs during S phase? What is interphase? How is the cell cycle controlled?

Describe mitosis. What are the phases of mitosis? What occurs in each of the phases of mitosis? What is cytokinesis? How does this differ between plant and animal cells? What is a kinetochore? Where does it form? What is its role? What is the role of microtubules in mitosis? What is a centriole and what is it composed of? What is a centrosome and what is its role in mitosis? What is the metaphase plate and why is this important? What is the mitotic spindle, its role and its makeup? What defines a diploid cell? How many copies of each chromosome is in a diploid cell? What about a haploid cell? Why do the daughter cells of mitosis always have the same complement of chromosomes?

Describe meiosis. What are the phases of meiosis? What occurs in each of the phases of meiosis? Distinguish between meiosis I and meiosis II and describe how each of these processes compare to mitosis. Why do animal cells undergo meiosis? What is a gamete? What is a zygote? What are recombination, crossing-over, and chiasma? When and why does this occur? What is meant by 'homologous pair of chromosomes'? Why don't the daughter cells of meiosis have the same genetic makeup? What controls the segregation of chromosomes into the gametes?

What are genetic characters? What are genetic traits? What is an allele? What is a locus? How many alleles at each locus would a human cell have and why? Distinguish between genotype and phenotype. What is meant by a dominant gene? What is meant by a recessive gene? How do these differ? What is the genotype of a homozygous dominant organism? What is its phenotype? What is the genotype of a homozygous recessive organism? What is its phenotype? What is the genotype of a heterozygous organism? What is its phenotype? What is a genetic cross? Distinguish between the P, F1, and F2 generations. What is a true-breeding line? What is the genotype and phenotype of a cross between homozygous dominant and homozygous recessive parents? If the F1 progeny are crossed, what would be the genotype and phenotype of the F2 generation? What would be the phenotypic ratio? What would be the genotypic ratio? Be ready to generate Punnet square tests or probability analyses of crosses involving more than one genetic locus. Describe a dihybrid cross where two alleles are homozygous dominant in one parent and homozygous recessive in the other. What would be the phenotypic ratio of the F2 generation from this dihybrid cross? What is meant by independent assortment? Be prepared to calculate probabilities resulting from different crosses.

Distinguish between complete and incomplete dominance. How would incomplete dominance alter the results of a hybrid cross? What would the resulting F2 generation phenotype and genotype ratios be? What is codominance? How does this affect the results of crosses? Be prepared to determine likely blood types of parents based on the blood types of their offspring. What is a polygenic trait? What is a carrier state for a genetic disease? What is meant by linked genes? How does this affect expected outcomes of genetic crosses? How is gene linkage used for chromosomal mapping? Distinguish between autosomes and sex chromosomes. What sex chromosomes are found in women? What sex chromosomes are found in men? What are sex-linked traits? Be prepared to give the results of crosses that involve sex-linked recessive traits. What is the process of nondisjunction? What are the likely results? Why is this important? What is a Barr body? Recognize the genetic abnormality of Downs Syndrome, Turner's Syndrome, and Klinefelter's Syndrome.

pucewallaby221

If an organismâs diploid chromosome number is 18, how many different possible combinations of homologous chromosomes lining up during meiosis exist for the eggs or sperm produced by that organism?

	A.	512
	B.	9
	C.	18
	D.	128
	E.	36

At the end of metaphase I, _______________ separate.

	A.	sister chromatids
	B.	germ cells
	C.	homologous chromosomes
	D.	haploid chromatids
	E.	centrioles

Mendel observed that dominant traits

	A.	are seen in all of the F1 hybrid pea plants in his experiments.
	B.	are expressed in all plants.
	C.	were absent in the F1 generation of pea plants that he used in his experiments.
	D.	were the only traits seen in the F2 generation of pea plants in his experiments.
	E.	are only expressed in hybrids.

Cytokinesis in plant cells differs from cytokinesis in animal cells because

	A.	there is no difference.
	B.	in plant cells, the cell plate must also divide into two parts.
	C.	the contractile protein, actin, is important only in plant cells.
	D.	plant cells have a rigid cell wall.
	E.	a contractile ring forms only in plant cells.

Sickle cell anemia is an example of what type of inheritance?

	A.	complete dominance
	B.	incomplete dominance
	C.	codominance
	D.	multiple alleles
	E.	recessive dominance

Which of the following statements is true:

	A.	The dominant allele is masked in homozygous dominant individuals.
	B.	With recessive genetic disorders, if both parents are carriers, the offspring will all be affected.
	C.	In carriers, the recessive allele causes an intermediate phenotype.
	D.	In recessive genetic disorders, the mother and/or father of an affected individual must also be affected.
	E.	With dominant genetic disorders, the mother and/or father of an affected individual must also be affected.

Skin cancers typically develop in the

	A.	upper layers of the epidermis.
	B.	lower layers of the dermis.
	C.	subcutaneous layer.
	D.	lower layers of the epidermis.
	E.	upper layers of the dermis.

Duchenne muscular dystrophy (MD) is inherited from an X-linked recessive allele. What is the probability that a son with Duchenne MD inherited this disease from his biological father?

	A.	1/2
	B.	0
	C.	1/16
	D.	1/4
	E.	1/8

The genetic makeup of a particular trait in an individual is its

	A.	genotype.
	B.	heterozygosity.
	C.	phenotype.
	D.	filial.
	E.	dominance.

What structure holds the sister chromatids to the spindle fibers?

	A.	chromatin
	B.	kinetochore
	C.	MPF
	D.	centromere
	E.	cyclin

If you view a cell in which the genetic material is beginning to be visible as separate bodies, and the nucleus has disappeared from view, you may surmise that the cells is in

	A.	telophase.
	B.	anaphase.
	C.	interphase.
	D.	metaphase.
	E.	prophase.

Gregor Mendel was successful in his analysis of the genetics of pea plants because

	A.	he examined and analyzed both the F1 and F2 generations.
	B.	he studied the parental plants to determine their differences.
	C.	he decided to only look at his results in an objective manner.
	D.	he studied a trait that had a strange inheritance pattern.
	E.	pea plants have genetics different from other organisms.

Tall corn plants (T) are dominant to dwarf plants (tt). Solid green leaves (G) are dominant to leaves with a white tip (gg). A cross between two corn plants yielded the following phenotypes: 51 tall plants with a white tip on their leaves; 43 dwarf plants with solid leaves; 48 dwarf plants with white tips on their leaves; 45 tall plants with solid leaves. What are the genotypes of the parents that produced these plants?

	A.	None of the above
	B.	TtGg x Ttgg
	C.	ttGG x TTgg
	D.	TtGg x TtGg
	E.	TtGg x ttgg

In humans, a gene that has been identified as causing a type of skin cancer is the

	A.	superwoman echidna.
	B.	mutant superman.
	C.	sonic hedgehog.
	D.	mutant mole rat.
	E.	superhero aardvark.

The segregation principle states that in sexually reproducing diploid organisms the two copies of each gene

	A.	segregate from each other during meiosis.
	B.	must always be the same allele.
	C.	separate from each other during mitosis.
	D.	will both wind up in either the sperm or egg.
	E.	move together as a unit during meiosis.

In what phases is the genetic material in the cell correctly referred to as chromatids?

	A.	metaphase and telophase
	B.	anaphase and metaphase
	C.	interphase and telophase
	D.	interphase and prophase
	E.	metaphase and prophase

Consider two traits for an organism, determined by two genes, each of which is governed by at least two alleles. In the case of a dihybrid individual, the gametes formed will be of either the parental type or the recombinant type. Recombinant type gametes are formed because of

	A.	the principle of dihybrids.
	B.	multiple alleles.
	C.	heterozygosity.
	D.	incomplete dominance.
	E.	independent assortment.

An allele is

	A.	an alternate form of a gene.
	B.	always recessive.
	C.	the main factor determining a trait.
	D.	always one of a pair.
	E.	the dominant form of a gene.

After the DNA is replicated, and it condenses in prophase, two identical rods of DNA are seen. These are

	A.	spindle fibers.
	B.	kinetochores.
	C.	chromatids.
	D.	chromatin.
	E.	centromeres.

Special cells found in the gonads that give rise to gametes upon division are called

	A.	egg cells.
	B.	somatic cells.
	C.	germ cells.
	D.	stem cells.
	E.	basal cells.

BIOL 1000 Lecture Notes - Lecture 9: Prophase, G0 Phase, Microtubule

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