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DAT BIOLOGY > ch 12- reproduction > Flashcards

ch 12- reproduction Flashcards

1
Q

binary fission

A

unicellular organisms
prokaryotes
mitochondria
chloroplasts

DNA replicated and migrates to ends of cells and SEPTUM forms

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2
Q

Budding

A

DNA replicated and deposited into bud

hydra and yeast do this

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3
Q

what does regeneration

A

hydra and planaria and fungi

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4
Q

parthogenesis

A

Unfertilized egg develops to a
viable organism (e.g., honeybees exhibit
haplodiploidy (males haploid, females diploid)).

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5
Q

spermiogenesis

A

final stage of spermatogenesis

haploid spermatids differentiate into mature motile spermatozoa (mature sperm cells)

NO CHANGE IN AMOUNT OF GENETIC MATERIAL

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6
Q

spermatogenesis

A

is the formation of mature
spermatozoa from spermatogonium. In this process,
diploid germ cells (spermatogonium) become haploid
gametes (spermatozoa).

produces four spermatids

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7
Q

seminiferous tubules

A

of testes are the site of
spermatogenesis (sperm production) and
contain:
● Sertoli cells: Surround and nourish sperm.
Produce inhibin (inhibits FSH - negative
feedback).
● Spermatogenic cells: Produce spermatozoa.

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8
Q

what activates sertoli cells

A

FSH

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9
Q

where are not mature sperm tranpsorted

A

from the seminiferous tubules to the epididymis via peristalsis

the epididymis is a duct around the testes

here the sperm are stored and matured

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10
Q

where does sperm go after the epididymis

A

Sperm moves through vas deferens (group of tubules) to ejaculatory duct (where vas deferens meets seminal vesicles) which propels sperm into
urethra and leads to ejaculation out of penis as semen (sperm + accessory gland secretions).

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11
Q

sperm parts

A

● Head: Contains nucleus and acrosome.
● Midpiece: Mitochondria (ATP production).
● Tail: Long flagellum (microtubules) to propel sperm.

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12
Q

seminal vesicle

A

accesory gland

Secrete fructose (nutrients to
produce ATP), viscous mucus (cleans and
lubricates urethra), and prostaglandins (causes
urethral contractions which propels sperm).

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13
Q

prostate gland

A

Alkaline secretions (basic) to
counteract uterine acidity.

accessory gland

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14
Q

bulbourethral gland

A

Viscous mucus (cleans and
lubricates urethra).

accessory gland

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15
Q

blastocyst

A

fertilized egg

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16
Q

what produces estrogen and progesterone

A

ovary

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17
Q

oogenesis steps

A
  1. Many oogonia produced, majority die via
    apoptosis, small fraction remain and differentiate
    to primary oocytes (begin meiosis but are
    arrested in prophase I until puberty).
  2. At puberty: one egg per month ovulates,
    completing meiosis I, which produces a large
    secondary oocyte (arrested in meiosis II during
    metaphase II) and a polar body.
  3. If fertilization occurs: meiosis II is completed.
  4. At the end of meiosis II: 2-3 polar bodies
    (non-viable) and 1 oocyte (viable, contains majority
    of cytoplasm, mitochondria, and nutrients for
    fetus) are produced.
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18
Q

when is meiosis I and II completed for eggs

A

I- puberty during ovulation one egg per month
-also produces polar body

II- after fertilization
-2-3 polar bodies by the end of meiosis II

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19
Q

FSH

A

Follicle stimulating hormone (FSH): Stimulates
follicles in the ovary to develop and production
of estrogen and progesterone.
● Follicles are fluid filled sacs on the ovaries that contain an immature egg (arrested at meiosis I). The corpus luteum is a temporary endocrine structure formed by the dominant follicle after ovulation of the egg.

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20
Q

LH

A

Stimulates ovulation
of egg, corpus luteum formation, which produces
estrogen and progesterone. The ovulated egg is
released from a dominant follicle to complete
meiosis I.

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21
Q

birth control pills

A

release
synthetic estrogen and progesterone, inhibiting
GnRH production during the menstrual cycle through
negative feedback and thus preventing the
menstrual cycle from causing ovulation.

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22
Q

temp dependent sex determination pattern 1 and 2

A

● Some reptiles determine their sex in
development not by chromosomes, but by
temperature.
○ Pattern I development results in males in
cold temperatures, and females in warm
temperatures (eg, turtles).
○ Pattern II development results in females
in low and high temperatures, and males
in intermediate temperatures (eg,
crocodiles).

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23
Q

factors influencing development- apoptosis

A

Programmed cell death is important for
normal development of the fetus (eg,
removing webbing between fingers) and
adults (preventing cancer).

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24
Q

factors influencing development- egg cytoplasm determinant

A

If egg cytoplasm is unevenly distributed
(creating animal and vegetal poles), an axis is created, influencing how the embryo divides during cleavage.

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25
factors influencing development- homeotic genes
master controller homeotic genes homeobox hox genes
26
master controller
turns different gene expressions on/off.
27
homeotic genes
decide which part of the embryo develops into what structures. ○ This is carried out through regulating the formation of the body axes and body structures in the proper location during early embryonic development.
28
homeobox
is a common DNA sequence homologous across organisms that contains homeotic genes.
29
hox genes
are a subset of homeotic genes that are responsible for anterior-posterior (head-to-tail) position of body parts during development.
30
ovoviviparity
Offspring develops in eggs that hatch within the mother's body. There is no placental connection, the embryos rely on the yolk sac in the egg. This is common in some snakes and amphibians.
31
viviparity
Offspring develops inside the mother’s body and are nourished via a placental connection. Most common in mammals.
32
oviparity
Offspring develops in eggs that hatch outside of the mother’s body. There is no placental connection between the mother and the eggs. Common in birds, fish, and reptiles.
33
what happens during the follicular phase
Hypothalamus releases Gonadotropin Releasing Hormone (GnRH) → anterior pituitary releases LH and FSH → FSH binds to the ovaries and induces follicles to develop → developing follicles release estrogen → endometrium thickens → rapid LH spike → ovulation.
34
what happens during ovulation
Ovulation (egg is released from Graafian follicle) → fimbriae on oviduct catches egg, cilia sweep egg into oviduct → egg travels down oviduct (awaiting sperm fertilization).
35
what happens during the luteal phase
Follicle develops into the corpus luteum (maintained by FSH and LH) → corpus luteum produces progesterone and some estrogen → uterine lining thickens (prepares for implantation).
36
what happens if no implantation occurs
LH and FSH levels drop (due to hypothalamus and pituitary inhibition by increased progesterone and estrogen) → corpus luteum can no longer be maintained → progesterone and estrogen levels drop (hypothalamus and pituitary are not inhibited anymore) → endometrium sloughs off (menstruation) → cycle repeats.
37
what happens if implanatation occurs
Outer layer of placenta produces human chorionic gonadotropin (hCG) → maintains corpus luteum → progesterone and estrogen levels maintained → endometrium remains (no menstruation).
38
hCG
hCG can be given to women during fertility treatment to trigger ovulation and enhance progesterone release.
39
lactation and childbirth
positive feedback loops ● Lactation: Infant suckling increases prolactin production which causes lactation (milk production) and further increases infant suckling. Oxytocin releases milk (milk let down reflex). ● Childbirth: Oxytocin induces contractions which push the baby out of the womb. The baby pushes against a nerve in the cervix that signals the hypothalamus and pituitary to release more oxytocin.
40
41
what are the negative feedback loops in reproduction
● The hypothalamus releases GnRH causing the pituitary to release FSH and LH which increase testosterone levels. High testosterone levels inhibit the hypothalamus from releasing GnRH, lowering FSH and LH and testosterone. ● The same occurs with estrogen and progesterone in the menstrual cycle.
42
where does fertilization occur
in the oviduct
43
female egg components
Outermost layer, corona radiata, nourishes developing egg. Underneath is the vitelline layer (known as the zona pellucida/jelly coat in mammals), made of glycoproteins. Plasma membrane is under the zona pellucida.
44
capacitation
Another maturation step for sperm prior to fertilization. Triggered by secretions in uterine wall and occurs in the oviduct. Destabilizes sperm plasma membrane proteins and lipids resulting in: ● Preparation of sperm tip for acrosomal reaction. ● Increased calcium permeability causing a hyperactive state (flagella beats harder, sperm swims faster).
45
acrosomal reaction
reaction: Recognition process between sperm and egg before fusion. Ensures same-species fertilization. Sperm goes through the corona radiata to reach zona pellucida. Actin from sperm binds to ZP3 protein of egg’s zona pellucida (mutual recognition). Membranes of sperm head and acrosome fuse, releasing hydrolytic acrosomal enzymes (hydrolases) to digest zona pellucida and allow sperm to fuse with plasma membrane of egg (fertilization).
46
polyspermy block
prevents polyploidy by inhibiting polyspermy (multiple sperms penetrating egg) fast block slow block
47
fast block
occurs first when sodium ions diffuse into the egg, depolarizing its membrane and prevents sperm binding.
48
slow block
Gradual, long-lasting occurs second. Calcium ions released in egg stimulate cortical reaction (exocytosis of cortical granules). Cortical granules make the vitelline membrane (jelly coat) impenetrable and stimulate proteases to separate the vitelline membrane from plasma membrane.
49
mitochondrial DNA
is inherited from the mother
50
cleavage
is rapid cell division without changing the total mass of cells. The subsequently smaller cells resulting from cleavage are called blastomeres.
51
axis of cleavage types
● Radial cleavage: cells aligned in vertical axis (eg. deuterostomes). ● Spiral cleavage: misaligned cells, deviate from axis (eg. protostomes).
52
determinate vs indeterminate cells
● Determinate (or mosaic) cleavage: Blastomeres have decided fate. ● Indeterminate (or regulative) cleavage: Blastomeres do not have pre-set fate. Cells that result from indeterminate cleavage are totipotent.
53
holoblastic vs meroblastic cleavage
evenness of division ● Holoblastic cleavage: Throughout entire embryo, evenly divides embryo, in animals with little yolk (eg. humans, sea urchins). ○ Exception: Frogs have lots of yolk and also undergo holoblastic cleavage that is uneven (exhibit polarity). ● Meroblastic cleavage: Partial cleavage, embryo not evenly divided, in animals with lots of yolk (eg. birds, fish, reptiles). Exhibits polarity with animal pole (active cleavage) and vegetal pole (mainly yolk, negligible division).
54
morule
(ball of blastomeres): Forms at 16-32 cell stage.
55
blastula stage
(hollow cavity): Forms at 128 cell stage. Blastocoel is hollow, fluid filled center.
56
blastocyst stage
Cells of blastula divide and differentiate.
57
cleavage occurs
as fertilized egg travels to the uterus
58
in the uterus
the fertlized egg is at the blastocyst stage
59
grastulation
Gastrulation is the formation of a trilaminar embryo. Epiblast cells invaginate inwards through the primitive streak to form three germ layers: endoderm, mesoderm, ectoderm. Embryo is now at the gastrula stage. As cells invaginate they create an opening called the blastopore, which forms the gut tube (archenteron), the center cavity that becomes the digestive tract.
60
ectoderm forms
● CNS (brain and spinal cord) and PNS, as well as neural crest cells and neural ganglia. ● Sensory parts of ear, eye, and nose. ● Epidermis layer of skin, hair, and nails. ● Mammary and sweat glands. ● Pigmentation cells. ● Enamel of teeth. ● Adrenal medulla.
61
mesoderm forms
● Bone and skeleton. ● Skeletal, smooth, and cardiac muscle. ● Cardiovascular system. ● Gonads. ● Adrenal cortex. ● Spleen. ● Notochord (induces spinal cord formation from ectoderm).
62
endoderm forms
● Epithelial lining of digestive, respiratory, and excretory systems. ● PLTT (Pancreas, Liver, Thyroid and parathyroid, Thymus).
63
organogenesis
formation of new organs
64
neurulation steps
is nervous system development: An embryo at this stage is known as a neurula. 1. Notochord stimulates ectoderm to thicken, forming the neural plate. 2. Neural plate folds onto itself forming the neural fold / neural groove. 3. Neural fold continues to fold, forming a hollow tube (neural tube). ● Some cells roll off to form neural crest cells (migrate to form teeth, craniofacial bones, skin pigmentation, etc.). 4. Neural tube differentiates into CNS. ● Mesoderm cells (somites) form two masses alongside notochord. Becomes vertebrae and skeletal muscles associated with axial skeleton.
65
totipotent
Totipotent stem cells can become any cell (eg. zygote, blastomeres of morula).
66
pluripotent
stem cells can become any of of the 3 germ layers (eg. ICM cells → embryonic stem cells).
67
multipotent
stem cells can only differentiate to a few cell types of a specific tissue type (eg. hematopoietic stem cell → many blood cells).
68
amnion
Amnion: innermost layer, membrane around embryo secretes amniotic fluid (water cushion, protecting embryo). ● Amniotes (reptiles, mammals, birds, marsupials) have an amnion, anamniotes (amphibians, fish) do not (surrounding water serves as cushion).
69
chorion
outermost layer. ● Placental mammals: forms fetal half of the placenta (platform for exchange of gases, nutrients, and waste). ● Egg-laying animals: membrane for gas exchange just underneath egg shell.
70
allantois
sac that buds off of the archenteron. Stores waste for disposal. ● Placental mammals: transports waste to placenta, becomes the umbilical cord, and in adults forms urinary bladder. ● Egg-laying animals: initially stores uric acid, later fuses with chorion (helps with gas exchange).
71
yolk sac
contains yolk (intraembryonic, provides nutrients). ● Placental mammals: transient function until placenta develops. First site of blood cell formation. ● Egg-laying animals: provides all nutrients for developing embryo.

DAT BIOLOGY (32 decks)

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