Lab Exam 1

Mitosis is traditionally divided into 5 stages:

1. prophase 2. prometaphase 3. metaphase 4. anaphase 5. telophase

how many chromatids does it have during metaphase

16

define centrosomes

2 microtubule organizing centers

human development requires nine months of development . human embryonic development encompasses _________.

2 months embryonic 7

Question 2a Lab 2 How many chromatids are involved in crossing over of a homologous pair of chromosomes?

4 chromatids

question 2 b lab 2 How many different combinations of these alleles would be possible?

4 combinations

question 3a page 243 lab 2 if a nucleus has eight chromosomes when it begins meiosis how many chromosomes does it have after telophase 1 and 2?

4 in telophase 1 4 in telophase 2

how many chromosomes have after mitosis is complete

8

chorion

Outermost layer of the two membranes surrounding the embryo; it forms the fetal part of the placenta.

describe zygote formation

a single sperm fertilizes an egg and the result is a zygote, the first cell of the new individual

umbilical cord

a tube containing the blood vessels connecting the fetus and placenta

48 hour check embryo - margin (edge) of the amnion

above vitelline arteries

define aster

arrangement of microtubules radiating from centriole

define kinetochore microtubules

attatch to each chromosomes kinetochore

define polar microtubules

axis of proteinaceous microtubules

To produce a new genetic combination each chromosomes initially pairs along its length with its homologous to form a ______. This pairing of homologous chromosomes is called _____, and the four chromatids exchange homologous segments of genetic materials called ____. This exchange of genetic material among chromatids is called ___ and produces new genetic combinations

bivalent, synapsis, alleles, crossing-over

48 hour check embryo - somites

blocks of developing muscles

define mitotic spindle

bridge of microtubules

describe early gastrula stage

certain cells push into blastocoel at blastopore

Question 5b page 239 lab 1 How does cytokinesis differ in plant versus animal cells?

cleavage furrow forms in animal cells but a cell plate forms across the equation of plant cell

in animal cells , cytokinesis include formation of ______ that begins on the periphery of the cell, pinches inward, and eventually divides the cytoplasm into two cells . In plants, cytokinesis includes formation of a partition called ___ perpendicular to the axis of the spindle apparatus.

cleavage furrow, cell plate

define kinetochore

complex of proteins that binds to centromere

yolk sac in mammal

contains blood vessels , first site of blood formation

yolk sac in chicks

contains yolk, food for developing embryo

48 hour check embryo- heart

contracting and circulating blood

define centrioles

cylinders of microtubules

48 hour check embryo - eye

developing lens

chromosomes in typical, eukaryotic nuclei occur in pairs; that is, the nuclei are ___ (2n). The two chromosomes of a par are called ____, and each homologous pair has the same sites, or loci, for the same genes, although homologous may carry different alleles at homologous loci. A nucleus such as that in a gamete, with only one chromosome of each homologous pair is ____.

diploid, homologous chromosome, haploid

fig 15.1 which shows meiosis produces ____ and ______ in animal, both of which are haploid. Fushion of an egg and sperm during fertilization produces a ____, which is diploid.

eggs, sperm, zygote

48 hour check embryo - caudal fold

embryo completely enveloped when head fold and caudal fold meet the margin

Primary germ layer - ectoderm . Pig adult structure-

epidermis of skin.: epithelial lining of oral cavity and rectum; nervous system

primary germ layer - endoderm pig adult structure -

epithelial lining of digestive , respiratory tract; associated glands of systems

48 hour check embryo - vitelline arteries and veins

extend over yolk . carry nutrients from yolk sac to the embryo

allantois in mammal

extends into umbilical cord

yolk sac

first embryonic membrane to appear

amnion in chick

forms amniotic cavity , envelopes embryo, contains amniotic fluid that cushions and protects

amnion in mammals

forms amniotic cavity , envelopes embryo, contains amniotic fluid that cushions and protects

amnion

forms amniotic cavity which envelopes embryo

chorion in chicks

functions in gas exchange

meiosis occurs in all sexually reproducing eukaryotes and produces haploid nuclei. _____ are reproductive cells with haploid nuclei resulting from meiosis and the formation of gametes is called _____. Meiosis is the primary element of gametogenesis and animals. Male gametes of mammals are different from female gametes. Gametogenesis includes _____ the formation of sperm cells and ____ the formation of egg cells

gametes, gametogenisis, spermatogenisis, oogenesis

describe late gastrula stage

gastrulation not complete until 3 layers of cells.

allantois

involved in early fluid exchange between the embryo and the yolk sac

spermatogenesis occurs in _____, made of tightly coiled tubes called ____.

male testes, seminiferous tubules

question 3b page 243 lab 2 what are the major differences between the events of meiosis and mitosis?

meiosis involves 2 cell divisions . mitosis is 1 cell division.

Question 5a page 239 lab 1 What region of a root has the most mitotic activity?

meristem

the early development of animals is quite similar , regardless of species. The fertilized egg or zygote undergoes too excessive divisions by cleavage forming a mulberry shaped ball of cells called a ______.

morula blastula blastocoel ectoderm endoderm mesoderm gastrula yolk germ layers

describe blastular formation

morula becomes blastula, hollow ball of cells

during nervous system development in the frog, two folds of ectoderm grow upward. The flat layer of ectoderm between them is the ____.

neural plate neural tube notochord vertebrae nerve cord brain

As soon as all 3 embryonic tissue layers are established the organ level development begins. The first organs to develop are the digestive tract, ______, and heart

neural tube / brain

chorion in mammals

outer layer surrounds inner mass at blastocyte stage becomes chorion

extraembryonic membranes

outside the embryo , they are "extra"

oogenesis occurs in ____ of females. Cells of the ovary that produce female gamete are called ____.

ovaries , oocytes, oogenia, primary oocyte prophase 1 follicular cells follicles ovulation graafian follicle haploid set

the extraembryonic membranes take their name from the observation that they are not part of embryo proper.

placenta capillaries umbilical cord allantois yolk sac

Placenta

provides nutrition and oxygen to embryo

48 hour check embryo - brain

several distinct regions

Primary germ layer - mesoderm Pig adult structure-

skeleton; muscular system; dermis of skin; cardiovascular, urinary, reproductive, outer layer digestive, respiratory

packed against the inner walls of the tubules are diploid cells called _______, which constantly replicate mitotically during the life of male. Some of the daughter cells move inwards toward the lumen of the tubule and begin mitosis. These cells are called _____. Meiosis 1 of a primary spermatocyte produces 2 ______, each with a haploid set of double stranded chromosomes. Meiosis 2 separated the strands of each chromosome and produces 2 haploid cells called ____. Spermatids mature and differentiate into _____ cells as they move along the length of the tubule.

spermatogonia, primary spermocytes secondary spermocytes spermatids sperm

48 hour check embryo - shape of embryo

started to bend, head is now almost touching the heart

allantois in chicks

storage area for metabolic waste

Question 5d page 239 lab 1 What is a cell plate? What state of mitosis does it form?

structure found inside the dividing of plant cells during telophase

Question 5c page 239 lab 1 Why is pinching of the cytoplasm inadequate for cytokinesis in plants?

the cell wall will stay intact

describe morula formation

zygote divides into a number of smaller cells until there is a cluster of 16 to 32 cells