Ch:10 Fertilization and Development

Question 1

Explain what occurs during the acrosomal reaction:

Answer 1

Enzymes punch a “hole” in the jelly while growing actin filaments form from the acrosomal process. Binding to the egg cell receptors occur!!

Question 2

Explain the process of fast block to polyspermy and compare it to slow block:

Answer 2

Contact and fusion of sperm and egg now occurs. The membrane voltage now changes… Depolarization. This results in what is called the fast block to polyspermy

The Cortical reaction (slow block): Ca++ ions are released from the endoplasmic reticulum. cortical granules in the egg fuse with the plasma membrane. Sperm-binding receptors are removed and a fertilization envelope forms. This forming of the fertilization envelope is termed slow block to polyspermy

(calcium is essential for the cortical rxn to occur)

Question 3

Continued cleavage gives a solid ball of cells called a ______. From here, a fluid-filled cavity called a ______ forms within this morula and begins to hollow. This hollow ball of cells is now called a ________.

Answer 3

Continued cleavage gives a solid ball of cells called a __Morula__. From here, a fluid-filled cavity called a __blastocoel__ forms within this morula and begins to hollow. This hollow ball of cells is now called a __blastula__.

Question 4

Put these in chronological order:

1. Zygote
2. Morula
3. Blastula
4. Gastrula

Answer 4

Zygote –> Morula –> blastula –> gastrula

Question 5

After the gastrula is formed a new central cavity is formed called the ________, which will become the primitive gut.

Answer 5

Archenteron

Question 6

The opening of the archenteron is called the _______. This opening forms the ____ in protostomes and the ____ in deuterostomes.

Answer 6

The opening of the archenteron is called the __blastopore__. This opening forms the mouth in protostomes and the anus in deuterostomes.

Question 7

Protostomes include: _____, _____, ______

Deuterostomes include: _____, _____

Answer 7

Protostomes include: mollusks, arthropods, annelids

Deuterostomes include: chordates and echinoderms

Question 8

What allowed arthropods to become successful?

Answer 8

Jointed appendages

Question 9

Which of the following has a closed circulatory system?

A. Arthropods
B. Annelids

Answer 9

A. Annelids

Question 10

Grasshoppers use _____(2 words)_____ to aid in metabolic waste removal.

Answer 10

Malpighian tubules

Question 11

Which of the following is high in yolk?

A. Vegetal pole
B. Animal pole

Answer 11

A. Vegetal pole

Question 12

In humans, the notochord becomes a ____(2 words)___ found between vertebrae

Answer 12

Gelatinous disk

Question 13

Tunicates and amphioxus are classified as _______, but are ________.

Answer 13

• Chordates

- invertebrates

Question 14

Amphibians and frogs are said to have evolved from ____________.

Answer 14

lobe-finned fish

Question 15

How many heart chambers are in the following:

1. Fish
2. Reptiles and amphibians
3. Birds and mammals

Answer 15

Fish = 2 chambered heart

Reptiles and amphibians = 3 chambered heart

Birds and mammals = 4 chambered hearts

Question 16

What does the endoderm give rise to?

Answer 16

• Epithelial linings of respiratory, excretory, digestive tracts, urinary bladder, and lining of reproductive systems and urethra
• Glands such as thymus, thyroid and parathyroid
• Liver and pancreas

Question 17

What does the mesoderm give rise to?

Answer 17

• Bone, muscle, blood, connective tissue, notochord, excretory, lymphatic and excretory system
• Dermis of the skin
• Adrenal cortex

Question 18

What does the ectoderm give rise to?

Answer 18

• hair, skin, nails, teeth, sweat glands, cornea and lens of the eye and the adrenal medulla

Outtermost layer- most sensitive to radiation!!!

Question 19

The greatest changes in cell shape and cell position occur in ______ and ______.

Answer 19

Gastrulation and organogenesis

As organogenesis progresses, morphogenesis (think shape) and cell differentiation continue

Question 20

Condensing of the mesoderm gives rise to the _______. This is a rod of stiffened tissue that serves as a support-like structure in all chordates.

Answer 20

Notochord

Question 21

Neural plate forms from the ______ and rolls into the neural tube which becomes the central nervous system.

Answer 21

Ectoderm

Question 22

Somites are formed… they represent block of mesoderm which give rise to _____ and ____.

Answer 22

Vertebrae and muscle

Question 23

Define all of the following:

• Yolk sac

- Chorion

Answer 23

Yolk sac: encloses the yolk and provides nutrients

Chorion: gas exchange, forms part of the placenta

Question 24

Define all of the following:

• Amnion

- Allantois

Answer 24

Amnion: absorbs shock and keeps embryo from drying out

Allantois: disposes of nitrogen waste and gas exchange. In humans it does not store wastes, but is involved in O2 and nutrient transport

Question 25

What is the difference between totipotent and pluripotent cells?

Answer 25

Totipotent is capable of developing into all different cell types (a zygote is totipotent plus the next three cell divisions)

Pluripotent: Think STEM CELLS! capable of developing into many cell types except extraembryonic tissues

Question 26

Implantation occurs in the _______ of the uterus and occurs before the end of the first week.

Answer 26

Endometrium

Question 27

The __1__ is what adheres to the endometrium. The __2__ is the mammalian version of a ___3___.

Answer 27

1. blastocyst
2. blastocyst
3. blastula

Question 28

Human gestation can be divided into three trimesters.

What occurs during the 1st trimester?

Answer 28

• most growth and differentiation occur here
• most sensitive to radiation and drug toxicity
• Main period for organogenesis
• After 8 weeks, the embryo is called a fetus

Question 29

What is the difference between viviparous and oviparous?

Answer 29

A viviparous development in means the young are born alive after being nourished in the uterus from the placenta

Oviparous means the young hatch from eggs laid outside the mother

Question 30

Human gestation can be divided into three trimesters.

What occurs during the 2nd trimester?

Answer 30

• all major organs are formed
• pregnancy is now obvious
• corpus lute deteriorates

Question 31

Human gestation can be divided into three trimesters.

What occurs during the 3rd trimester?

Answer 31

• around 8 months the fetus can survive on its own

Question 32

What is a homeotic gene?

Answer 32

Homeotic genes are regulatory genes that are responsible for the placement and spacial organization of body parts