Quiz 2 of Exam 3 ACE BIO 2

an areas of interest was never posted so this will be my study guide for the quiz

Composition of sperm

head(acrosome)

midpiece

tail

The two events of fertilization

union of egg and sperm nuclei and the activation of egg to begin development

Barriers used to prevent sperm penetration

corona radiata—layer of cells that chemically attracts sperm(the sperm must navigate through this)

Zona Pellucida—highly protective layer surrounding secondary oocyte

Fast block mechanism—temporary change in polarity of egg’s plasma membrane

Slow block mechanism—permanent chemical changes

Polyspermy

fertilization by more than one sperm cell

During early development the egg and sperm merge into

a zygote(diploid)

Cleavage causes

early mitotic cell divisions

provides raw material

Morula vs blastula

morula is a solid ball of cells(16 cell divisions)

blastula is a hollow ball of cells(32 cell division)

Blastocoel

fluid filled interior

blastocyst

more complex version of blastula found in mammals

trophoblast

prevents an immune response by mother, becomes embryonic supporting tissues

Three germs layers formed by gastrulation

ectoderm—

mesoderm—

endoderm—

Diploblastic s triploblastic species

diploblastic has only ectoderm and endoderm

triploblastic has ectoderm, endoderm, and mesoderm

Protostome vs deuterostome

protostomes become the mouth

deuterostome becomes the anus

first pair of gill arches becomes the __ and the next three pairs become ___

First pair becomes the middle ear bones, inner ear, and eustachian tube

Next three pairs become various glands

Amniotic egg vs placental mammals

Amniotic egg has albumin which is the egg white; it provides protection, shock absorption, and maintains a moist environment

Extraembryonic membranes in amniotic egg:

yolk sac—provides nutrients to embryo

amnion—provides protection and shock absoprtion

chorion—gas exchange

allantois—collects waste from embryo, merges with chorionic later in development

Placental mammals have implantation—embyro reach's uterus as blastocyst

Extraembryonic membranes in placental mammal:

yolk sac—no nutritional function, part of umbilical cord, first site for blood cells formation

amnion—amniotic cavity/fluid

chorion—joins with blood vessels and part of endometrium→placenta(there is NO mixing of maternal and fetal blood)

allantois—forms most of umbilical cord → placental connection; it contributes to formation of umbilical cord vessels

First trimester vs second trimester vs third trimester

First—digestive and respiratory systems begin to form, limbs form, reproductive system begins in an indifferent state(if there is testosterone present, it is male, if not, female)

Second—further growth and refinement, organ systems approach functional state, fetus begins breathing motions

Third—organ systems and nervous system nearly functional, ossification of bone begins (Fetal cartilage is replaced by bone; continues after birth)

Birth

caused by an aging placental and changing levels of progesterone

Rising levels of hormones induce labor contractions; the hormones are oxytocin, androgens, and prostaglandins

the three stages of birth

1st stage—dilation of cervix

2nd stage—crowning, baby is born

3rd stage—placenta is delivered

Aging

aging is the accumulation of changes in an organism over time

menopause

when the menstrual cycle ceases and ovaries stop functioning; usually between the ages of 45 and 55

preprogrammed theories vs damage control theories

preprogrammed theories—aging is genetically programmed; apoptosis is cell death, and we age when apoptosis is greater than mitosis

genes count for 25% of why we age

Damage control theories—aging is caused by accumulation of cellular damage over time such as:

Harmful mutation

Buildup toxins

Poor diet

Over-exposure to sun

Death

death is the cessation of sustaining metabolism

All cells that cease mitosis or meiosis die(apoptosis)

Organisms avoid death through:

cell modifications in metabolism, shape and reproduction, examples are: forming tough spores or capsules, producing anti-attacker substances, and lowered metabolism in response to stress

Cells die because

newer ones will live; death makes reproduction the biological imperative

Reproduction allows DNA to survive and change(mutate) and this leads to evolution, evolution leads to adaptation

Why is death important?

death is important ecologically because it keeps populations in check by reducing numbers, death leads to decay, and decay allows nutrients to be recycled back into nature

polarized eggs

egg cells in which the cytoplasmic constituents are not equally distributed

animal hemisphere vs vegetal hemisphere

animal—division of a polarized egg which contains the more metabolically active organelles

vegetal—division of a polarized egg that is less active and contains food reserves in the form of yolk

gastrulation

a critical event in the development of all animals; involves the inward movement and reorganization of cells of the blastula or blastocyst into a gastrula; it results in the formation of three germ layers(endoderm, ectoderm, mesoderm)

coelomate organisms vs pseudocoelomate organisms vs acoelomate organisms

coelomate—organisms that have their body cavities completely lined with or derived from medoderm

pseudocoelomate—thos whose body cavities are incompletely lined with or derived from mesoderm

acoelomate—those organisms that lack a true body cavity

morphogenesis

developmental processes that produce the general shape and form of the animal’s body

progenitor cells vs ES cells

progentitor—embryonic stem cells that are limited in what other cell types they can differentiate into

ES cells—the earliest cells of a developing embryo(can turn into a progenitor cell)

Fertilization

the union of two haploid nuclei