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biology development 2


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list the two functions of fertilization?
to create genetic variation and fuse a sperm cell with and egg, and form a diploid cell known as a zygote.
Describe the acrosomal reaction and explain how it ensures the gametes are conspecific.
1.) contents of acrosome are expelled and enzymes are released digest a pathway through eggs jelly layer and allow sperm to reach vitelline envelope of egg. 2.) polmerization of actin into microfilamentast that form acrosomal process. finally, plasma membranes of egg and sperm fuse. sperm nucleus, mitochondria, and centriole enter egg. sperm and eg nuclei fuse--forms zygote.
explain the cortical reaction.
3. layer splits off of the egg. The egg has a whole series of vesicles at surface that fuse and dumps contents into the vatellin layer. Molecules are there to increase osmolarity to fill with water and pull the surface away. Then hardens and becomes a permanent surface. To get a vesicle to fuse with surface you need a small change in the calcium. It comes from the endoplasmic reticulum that has extra calcium. Need to trigger its release from the ER, the signal comes from the sperm, might take a min to take place from once side of cell to the other side of the cell.
explain how the acrosomal and cortical reactiosn function sequentially to prevent polyspermy.
4. The entry of a sperm causes calcium ions (Ca2+) to be released from storage areas inside the egg. In response to the dramatic increase in calcium concentration, a series of events occurs in the egg. For example the cortical granules located just inside the membrane fuse with the egg cells plasma membrane and release their contents to the exterior. The contents of the crtical granules include proteases that digest the exterior-facing fragment of the egg-cell receptor for sperm. In addition, other compounds from the cortical granules are trapped between the egg cell’s plasma memebrane and the vitelline envelope and cause water to flow into the space by osmosis. The influx of water then causes the envelope matrix to lift away from the cell and form a fertilization envelope. The fertilization envelope, in turn keeps additional sperm from contacting the egg membrane.
describe the changes that occur in an activated egg and explain the importance of cytoplasmic materials to egg activation.
5. *The cytoplasmic determinants direct cleavage in the egg. New RNA start to be produced after the twelfth cleavage division. Until then, development is directed by cytoplasmic determinants. The cytoplasmic determinants also orientation the mitotic spindle. The orientation of cleavage is controlled by the mitotic spindle. Different pigment cells might mark individual cells and allow researchers to follow their fate as development progressed. The fate is what the cell is likely to become in the adult individual. (p.455)
describe the process of gastrulation and explain its importance.
7. Gastrulation radically rearranges cells and results in formation of gastrula, which contains the three embryonic tissue types. The three tissue types are extoderm, mesoderm, endoderm. PROCESS-
⬢ blastula contain cytoplasmic determinants that determine their fate during gastrulation.
⬢ Gastrulation begins with the formation of an opening midway between the poles. Cells from the surface move to the interior through a blastipore.
⬢ The blastocoel shrinks as the surface cells continue to move inward, forming the three embryonic tissue layers
⬢ The three embryonic tissue layers are formed, ready for organogenesis. The blastopore (future anus in frogs*) surrounds a plug of yolk cells.
list adult structures derived from each of the primary tissue layers.
⬢ Ectoderm
i. Nervous system, cornea and lens of eye, epidermis of skin, epithelial lining of mouth and rectum.
⬢ Mesoderm
i. Skeletal system , circulatory system, lymphatic system, muscular system, excretory system, reproductive system, dermis of skin, lining of body cavity
⬢ Endoderm
i. Epithelial lining of: digestive tract, respiratory tract, reproductive track, and urinary tract.
ii. Liver, pamcreas, thyroid, parathyroids, thymus.
distinguish between meroblastic cleavage and holoblastic cleabage.
holoblastic- total cleavage
meroplastic- partial cleavage
list and explain the functions of the extraembryonic membranes
1. amnion
a. thin, ectoderm-derived innermost membrane
b. produces amniotic fluid to bath embryo
c. reptiles, bird, and mammals are referred to as amniotes.
2. yolk sac
a. endoderm-derived
b. associated with nutrition in reptiles and birds
c. retained in mammals because it is the source for primordial germ cells and
original circulating blood cells
3. allantois
a. endoderm-derived
b. reptile/birds – reservoir for wastes and mediates gas exchange
c. mammals – associated with fetal-maternal interface at placenta
4. chorion
Four sets of extraembryonic membranes common to vertebrates.
a. mesoderm-derived, outermost layer
b. reptile/birds – gas exchange
c. mammals – involved in respiration, nutrition, excretion, filtration, and hormone
synthesis by producing fetal placenta
process by which a cell becomes a cell becomes a particular cell type by differential gene expression
process of embryonic development during which cells become organized into arecognizable tissues, organs, and other surfaces.
the union of a sperm and egg
fetilized egg
enzymes found on head of sperm cell that helps dissolve zona pellucida or jelly layer on egg.
acrosomal reaction
a response that is triggered by contact between the sperms head and the jelly layer
acrosomal vesicle
holds acrosome in sperm
acrosomal procerss
a protrusion that extens until it makes contact with the viteline envelope
protein that is on the head of a sea urching sperm that binds to the surface of the eggs in a species- specific- manner
vitelline layer
outside plasma membrane, fibrous, mat-like sheet of glycoproteins, surrounds egg, in humans=zona pellucida
fast block to polyspermy
formation of fertilization envelope
cortical granules
small vesicles filled with enzymes that are involved in fertilization in egglaying animals. synthesized, transported to cell surface and bound to inner surface of plasma membrane as egg matures
rapid cell divisions that take place in animals after fertilization
cells created by cleavage divisions
vegetal pole
yolk-rich reagion
meroblastic cleavage
cleavage is restricted to only part of the cell
holoblastic cldavage
cleavage plane cuts through tentire cell, including
an embryo at an early stage of embryonic development, consisting of approximately 12-32 cells
cerntral region of a blastula (or blastosphere). It is filled with fluid.
sphere of cells that formss when cleavage is complete
coordinated cell movements that result in a formation of a layered body structure.
small pore of vertebrate embryo, through which cells move during gastrulation
embryo after gastroulation with three germ layers but with no nerve cord
indentation in cell that starts gastrulation
primitive gut
outside-skin, epidermis of skin, forms outer covering and nervous system, forms skeletal muscle, and lens of eyeball
middle skin, gives rise to muscle, internal organs such as blood and cartilage.
inner skin, produces lining of digestive tract or gut, along with organs.
long, gelantinous, supportive rod down back of chordate embryo, below developing spinal cord, replaced by vertebrae in adult vertebrates, defining feature of chordates
neural plate
flat formation in gastroula that preceded the neural crest and tube.
neural tube
folded tube of ectoderm that forms along dorsal side of vertebrate embryo, gives rise to brain and spinal cord.
yolk platelets
discs full of yolk
dorsal lip
find out
yolk plug
large food-laden endothermal cells surrounded by the blastopore of an amphibian gastrula
a block of mesoderm on both sides of the developing spinal cord in a vertebrate embryo, gives rise to muscle tissue, vertebrae, ribs, limbs.
neural crest
group of embryonic cells that separate from the neural plate during neurolation and migrae to give several different lineages of adult cells.
determined cell
cells that cannot change, they have their function
animal pole
yolk poor region of an egg cell
positional information
info that cells use to determine what they are going to be in respect to their relative position
substance governing the pattern of tissue development, positions of the various specialized cell types within a tissue
yolk sac
amniotic egg, membranebound sac that contains the yolk
membrane in amniotic egg that surrouds embryo and encloses it in a protective pool of fluid
amniotic egg, highly vascularized membrane across which gas exchange occurs.
amniotic egg, membrane-bound sac that holds waste materials.
inner cell mass
group of cells found in the blastocyst, which give rise to embryo, it can make anything (tissues, organs) except trophoblast
provides nutrients to fetus, eventually forms placenta
embryonic disc
forms floor of amniotic cavity, derived of inner mass
gray crescent
gray cytoplasm in zygotes of some frog species opposite the point of sperm entry
capable of dividing and developing to form complete, mature organism
cytoplasmic determinant
a molecule that exists in eggs and helps early development
fate map
description of what each cell in the embryo is destined to become.
pattern formation
events that determine spatial organization of embryo, including major body axes and orientation of limbs
retinoic acid
vitamin A, cause of cell differentiation, plays part in growth and development in embryo. higher concentration causes growth of extra limbs
extramembryonic membranes
membrane that connects mother to child
interaction between a signaling cell and a nearby recipient cell that changes the activity or fate of the recipient cell.
region of amphibian embryo that can organize development of entire embryo cells that do recruiting, which come from specific fegion on the embryo's dorsal side.
primitive streak
where invagination eventually occurs
epithelial tissue
covers outside of the body, lines surfaces of organs, and forms glands. acts as a barrier and protective layer, typically form layers of closely packed cells. adjacent cells are joined by structures that hold them together (tight junctions and desmosomes).
simple epithelial cell
one layer of flat cells
rectangular cells, epithelial cells whose heights are at least twice their width. divided into simple, or unilayered, and stratified, or multi-layered
elastic fiver
bundles of proteins (elastin) found n connective tissue, produced by fibroblasts and smooth muscle cells in arteries
long projection of a neuron that can propagate an action potential
only cells found in cartilage
immune system cells, including neurtrohils, macrophages, b cells and t cells, circulate in blolod or lymph and functin in defense against disease. (white blood cells
cardiac muscle
tissue of the vertebrate heart, consists of long branched fibers that are electrically connected that initiate their own contractions, not under voluntary control.
short extension from a neurons cell body that recieves neurotransmitters from other neurons
connecective tissue
cells loosely arranged in a liquid, jellylike, or soldid extracellular matrix
stratified epithelia
layered epithelial cells
flat cells
reticular fibers
very thin, delicately woven strands of collagen, strands build highly ordered cellular network and provide support
structure that seves a specialized function and consists of several tissues
most abundant cell found in bone
Red blood cells
visceral muscle
smooth muscle
fibrous connective tissue
type of connective tissue which has relatively high tensile strength, due to a relatively high concentration of collagenous fibers
muscle tissue
tissue consisting of bundles of long, thin contractile cells (muscle fibers)
1 layer, which looks like 2 because of the position the nuclei.
loose connective tissue
contains an array of fibrous proteins in a soft matrix and serves as a packing material between organs or padding under the skin.
fiber for connective tissue
band of tough, fibrous connective tissue that connects a muscle to a bone.
Haversian system:
Osteons (also called Haversian system in honor of Clopton Havers) are predominant structures found in some lamellar or compact bone.
small membrane-bound cell fragment in vertebrate blood, important in blood clotting
nervous tissue
tissue consisting of nerve cells (neurons) and various supporting cells, and functioning in rapid transmission of complex information
cube shaped cells, nucleus in the center of cell
collagenous fibers
made of collagen, bundles of fibrils that are coils of collagen molecules
adipos tissue
fat tissue
short band of tough fibrous connective tissue composed mainly of long, stringy collagen fibers
type of liquid connective tissue consisting of red blood cells and leukocytes (white blood cells) suspended in fluid plasma.
skeletal muscle
(striated muscle): muscle tissue attached to bones of vertebrate skeleton, consists of long, unbranched muscle fibers w/characteristic striped (striated) appearance; voluntary control.
: nerve cell, specialized for transmission of nerve impulses, has dendrites, cell body, and long axon that forms synapses with other neurons.
plant that has single cotyledon upon germination
abscisic acid
ABA, plant hormone that inhibits cell elongation, stimulates leaf shedding and dormancy
plant vascular tissue conducts sugar, amino acids, chemical signals, contains sieve-tube members and companion cells
vascular tissue system
parenchyma and sclerenchyma cells specialized for support and long-distance transport of water and nutrients. (xylem, phloem)
involuntary positional growth response to a stimulus
indeterminate growth
a pattern of growth in which organism continues to increase its overall body size throughout life
movement or growth of a plant in response to gravity, caused by asymmetrical distribution of auxin in roots
vertical aboveground part of a plant usually bearing leaves, fruit, flowers
part of stem where leaves or leaf buds are attached
section of a plant stem between 2 nodes (site where leaves attach)
axillary bud
lies at the junction of the stem and petiole of a plant
apical dominance
growth habit in which most of stem’s growth occurs at the apical meristem of the shoot
parenchyma cell
found in all tissue systems, living cells, capable of further division (totipotent), thin primary wall (found in leaves, centers of stems and roots, fruits. Involved in photosynthesis, starch storage, new growth)
collenchyma cell
living cell, thicker cell wall, elongated and packed into long ropelike fibers. Provide mechanical support in ground tissue system or elongating plants
sclerenchyma cell
strengthening and supporting function, dead cells w/thick lignified secondary cell walls, prevent them from stretching as plants grow.
plant w/2 cotyledons upon germination
plant vascular tissue conducts water and ions from root system to shoot system. Contains tracheids and vessel elements
waxy layer that overlays epidermal cells of shoot system, minimizes water loss, forms barrier that protects plant from virus particles, reduces gas exchange, protects from damaging effects of intense sunlight and attacks from herbivores.
leaf abscissin
shedding of leaves from a plant
root hair
outgrowths produced by epidermal cells, greatly increase surface area of dermal tissue, furnish actual sites of water and nutrient absorption
indoleacetic acid (IAA)
hormone, molecule that produced bending response in decapitated shoots
acid-growth hypothesis
auxin’s effect on plant cell elongation occurs via installation of proton pumps that make cell wall more acidic, causing cell wall to expand.
vessel elements
elongated water-conducting plant cell founding xylem. Has gaps thru both primary and secondary cell walls, allowing unconstrained passage of water from one cell to the next.
plant hormone that stimulates growth
apical meristem
grp of undifferentiated cells at the tip of stem or root of a vascular plant, responsible for primary growth
simple tissue
: plant tissues that consist of a single cell type
dermal tissue system
: plants protective outer covering, facilitates water and ion uptake in roots and regulates gas exchange in leaves and stems
: gaseous plant hormone that induces fruit to ripen, flowers to fade, and leaves to drop. (assoc. w/senescence (process of aging)
ground tissue system
plant tissue consisting of all cells beneath the outer protective layers of epidermis and cork, expect for vascular tissue.
growth or movement in a particular direction in response to light
ground meristem:
middle layer of young plant embryo, gives rise to ground tissue
group of cells in core of embryo that becomes vascular tissue
: plant hormones that promote cell division, active cytokinins are synthesized in apical meristems of roots and transported in apical meristems of roots and transported into shoot system thru xylem
protective cells that cover growing region of root
zone of cell division
contains apical meristem, where cells are actively dividing
complex tissue
tissues that contain several types of cells
stress hormone:
cortisol and norepinephrine are released at periods of high stress. The hormone regulating system is know as the endocrine system. Cortisol is believed to affect the metabolic system and norepinephrine is believed to play a role in ADHD
taproot system:
large vertical main root of a plant
indoleacetic acid, plant hormone that stimulates phototropism, involved in cell elongation and apical dominance, promotes cell division and leaf expansion, encourage ethylene production
group of undifferentiated plant cells that can produce cells that differentiate into specific adult tissues.
exterior layer of plant embryo, gives rise to epidermis
sieve plates
pore-containing structure at one end of a sieve-tube member in phloem
stalk of leaf
elongated water-conducting plant cell w/gaps (pits) in secondary cell wall to allow water movement from once cell to next
plant that lives for more than 1 year.
flowering plant, produces flowers, flowers contain both male and female parts, produces seeds within mature ovaries
monocotyledons dicotyledons
1 cotyledon (inside seed) 2 cotyledons
vascular tissue scattered throughout stem vascular tissue in circular arrangement in stem
parallel veins in leaves (bundles of vascular tissue) branching veins in leaves
flower petals in multiples of 3 flower petals in multiples of 4/5
2 cotyledons
vascular tissue in circular arrangement in stem
branching veins in leaves
flower petals in multiples of 4/5
The importance of root system is to anchor the plant, take in water and nutrients from the soil, and serve as a storage site for starch and carbohydrates. The shoot system harvests light and CO2. The root system provides the shoot system with water and k
Simple tissues
plant tissues that consist of single cell type
Complex tissues
plant tissues that contain several cell typesCuticles are needed for overlaying the epidermal layer of the shoot system.
used to minimize water loss by their wax, which is a lipid and hydrophobic. reduce amount of water that is lost thru evaporation from dermal tissue. protect the plant against pathogens by forming the first line of defense. Reduce gas exchange (open or closed stomata) Protection against sunlight and attacks by herbivores. Roots do not need protection because they are in the ground, therefore no intense sunlight, no herbivores. They have dead cells there that may be eaten
: Vascular tissue system
xylem and phloem (form continuous vascular system throughout plant), conducts water and solutes between organs and mechanical support
5 classes of plant hormones:
auxin: bends stems of plants towards light (phototropism), inhibits lateral bud development, cell elongation, organogenisis
ethylene: ripens plants, promotes leaf abscission
gibberellin: promotes seed germination, cell division and elongation, breaks seed dormancy
ABA: inhibits seed germination, promotes seed dormancy and winter dormancy
Cytokinin: promotes cell division and differentiation, inhibits leaf abscission.
Light causes a phototropic response by wavelengths in the blue part of the electromagnetic spectrum being detected by photoreceptors (phototropins). It activates the hormones, which is produced in one part of the plant, and transported to target cells in another region of the individual, where it causes physiological responses.
Small Intestine-
first site of the intestine, immediately after the stomach, site of the final stages of digestion and of most nutrient absorption.
A gland attached to the small intestine that secretes digestive enzymes into the intestine and several digestion-related hormones (notably, insulin and glucagons) into the bloodstream.
a dimer, found in inactive form of maltose
enzyme that breaks down starch.
on the brush border.
protein-digesting enzyme produced by the pancreas, secreted into the intestine, and activated by enterokinase, activates several other protein-digesting enzymes.
An enzyme that trypsin activates.
- carboxypeptidase’s-
An enzyme that trypsin activates.
breaks up long amino acids into shorter ones.
An intestinal enzyme that converts trypsinogen (from the pancreas) to active trypsin, which then activates protein-digesting enzymes.
Acid in your stomach. Needs to be carefully controlled b/c it can destroy small intestine cells. It needs a buffer (HCO3-).
Tiny protrusions from the surface of an epithelial cell that increase the surface area for absorption of substances.
breaks down lactose.
saliva Breaks down starch so we won’t choke and to keep our teeth healthy
The last part of the digestive tract; a short tube that hold feces until they are expelled.
Pancreatic Amylase
- Continues the digestion of carbohydrates that began in the mouth . It is secreted from the pancreas into the small intestine.
The ball of food that the tongue shapes so you can easily swallow it.
The muscular tube that connects the mouth to the stomach
- Lymphatic vessels in the center of villi of the small intestine. Receive chylomicrons containing fat absorbed from food and send them into the lymph system.
A fluid produced by the liver, stored in the gall bladder and secreted into the intestine, where it emulsifies fats during digestion.
When fat molecules are broken up
Second part of the small intestine.
Rhythmic waves of muscular contractions of muscular contraction that push food along the digestive tract.
Any enzyme that can digest fats.
Salivary amylase-
an enzyme within the mouth that softens food and breaks down starch.
Intestinal hormone. Stimulates the release of digestive enzymes. From the pancreas.
- Stomach
A tough, muscular pouch in the digestive tract that breaks up food and delivers it to the intestine.
Large stomach (colon)-
Compact the wastes that remain and absorb enough water to form feces.
The inactive forms of enzymes. The enzymes are in inactive form in order to prevent the body from eating itself.
A slimy mixture of glycoproteins and water, secreted by organs for lubrication.
Goblet cells-
A blind sac between the small intestine and the colon. Used in some species as a fermentation vat for digestion of cellulose.
Salivary glands
Release water and glycoproteins called mucins (when touch water, it forms mucus).
An abdominal organ of vertebrates that performs many biochemical processes, including storage of glycogen, processing and converting of food and wastes, and production of bile.
A mixture of polysaccharides amylose and amyl pectin; used primarily for food storage in plants.
Cardiac sphincter-
Connects the esophagus to the stomach.
Pyloric sphincter
Connects the stomach to the doudenum (the small intestine).
a substance within the mouth that contains amylase that softens and breaks down starch.
The non-harmful form of pepsin(ogen). Digests proteins in the stomach.
A peptide hormone produced by the small intestine in response to the arrival of food from the stomach. Stimulates secretion of bicarbonate from the pancreas
A hormone produced by the stomach in response to the arrival of food or to a signal via nerves from the brain. Stimulates other stomach cells to release hydrochloric acid.
projections of the lining of the digestive tract. Function to increase surface area for absorption.
Bile salts
Small lipids in bile that emulsify fats
The first part of the small intestine.
Digest the RNA and DNA in food.
An enzyme that breaks down starch
The third part of the small intestine
the basic form of lipid when it is broken down for digestion.
- A ball of protein-coated lipids, used to transport the lipids through the bloodstream.
Vasopressin (ADH)-
Synthesized in the hypothalamus and released from the pituitary gland. Increases the permeability of the kidney’s collecting ducts to water. As a result, water is reabsorbed from the urine and saved. Instrumental in achieving homeostatis.
A hormone that is released from the hypothalamus and induces labor and milk production in females.
Sits below the hypothalamus and has distinct anterior and posterior regions; releases the growth hormone, ACTH, TSH, prolactin, FSH and LH.
- - Synthesis of new glucose from non-carbohydrate sources, such as proteins and fatty acids. Occurs in the liver response to low insulin levels and high glucagons levels.
Increases reabsorption of sodium by kidneys. Released from the adrenal glands
Growth hormone
A peptide hormone produced by the mammalian pituitary gland. Involved in lengthening the long bones during childhood and in muscle growth, tissue repair, and lactation in adults.
Released from the pituitary gland. Stimulates the mammary gland growth and milk production in females.
A disease where the growth hormone is overproduced. It results in a person being very tall.
A peptide hormone produced by the pancreas in response to high levels of glucose (or amino acids) in blood. Enables cells to absorb glucose and coordinates synthesis of fats, proteins, and glycogen.
A peptide hormone produced by the pancreas response to low blood glucose. Raises blood glucose by triggering breakdown of glycogen and stimulating gluconeogensis
A part of the brain that regulates the body’s internal physiological state, such as the autonomic nervous system and the endocrine system.
Releasing factor-
A hormone that stimulates the release of other hormones
Inhibiting factors
A hormone that inhibits the release of other hormones
Adrenal cortex
Completely different gland from adrenal medulla. Makes steroid hormones.
Adrenal medulla-
- Produces two different hormones 1) epinephrine (adrenaline), 2) nor epinephrine.
A class of steroid hormones released from the adrenal cortex that increase blood glucose and prepare the body for stress. Its primary role in humans is to ensure the continued availability of fuel molecules to support important body functions.
A signaling molecule that circulates throughout the body in blood or other body fluids; can trigger pronounced responses in distant target cells at very low concentrations.
A catecholamine hormone from the adrenal medulla. Triggers rapid responses relating to the fight-or-flight response. Also known as adrenaline.
Help regulate the blood calcium level. It decreases the calcium in blood. It is released from the Thyroid gland.
A peptide hormone that increases the calcium levels in blood.
peptide hormone from the pituitary gland that stimulates release of thyroid hormones from the thyroid gland.
Stimulated from the pituitary gland. It stimulates adrenal glands to secrete glucocorticoids
Trophic hormone
hormones that control the release of other hormones
Thyroid gland-
Situated in the neck. Releases thyroxin and calcitonin
Regulates the metabolic rate. Increases the metabolic rate and heart rate; promotes growth. It is released from the thyroid gland.
Parathyroid gland
- Embedded in the thyroid gland; releases PTH (increases the calcium in blood)
Adrenal gland
Two glands that sit atop the kidney and have an outer cortex and a central medulla. Release epinephrine, cortical and aldosterone.
- name for a large region within the brain that is attributed many functions.
the system of membranes that envelop the central nervous system
White matter
one of the two main solid components of the central nervous system . It is composed of myelinated nerve cell processes, or axons, which connect various grey matter areas (the locations of nerve cell bodies) of the brain to each other and carry nerve impulses between neurons.
Grey matter
major component of the central nervous system, consisting of nerve cell bodies and short nerve cell extensions/processes ( axons and dendrites).
azon terminal branches

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