Lecture 24

Biology 101 with Other at University of Pennsylvania

About this deck

By: Aaron Fedor
Textbook:

Campbell Biology (9th Edition)
Study Guide for Campbell Biology
Created: 2012-04-15
Size: 76 flashcards
Views: 6

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asexual reproduction

the creatin of offspring without the fusion of egg and sperm. results in offspring that are genetically identical to one another and to their parents. mechanisms are: budding, fission, parthenogenesis.

budding

asexual reproduction where offspring begin to form within or on a parent by fragmentation. process is completed when offspring breaks free and begins to grow on its own

fission

asexual reproduction where an individual simply splits into two or more descendants

parthenogenesis

asexual reproduction where offspring develop from unfertilized eggs, which are identical to the mother

sexual females have half as many daughters as asexual females.

how many daughters does a sexual female have in comparison to asexual. this is called the "twofold cost" of sexual reproduction. still, most eukaryotes replicate this way

sexual reproduction: gametogenesis, fertilization(including mating). gene reshuffling mechanisms: ind. assort. of chromosomes, crossing over, random fert.

depends on meiotic cell division, consists of two fundamental steps (which are?) contributes to genetic variation within a species by reshuffling existing versions of genes using three mechanisms (which are?)

meiosis

4 haploid daughter cells with half as many chromosomes as the parent cell are reproduced in diploid org. (vs 2 diploid daughter cells in mitosis). two divisions occur: meiosis I and II, preceded by interphase. includes chromosomal exchange via 'crossing over'

gametogenesis

collectively, the mitotic cell divisons, meiotic cell divisions and developmental events that result in product of male (sperm) and female (egg) gametes. includes spermatogenesis, oogenesis

spermatogenesis; primary speratocytes; secondary spermatocytes; spermatids; sperm

formatin of the sperm. part of gametogenesis. when spermatogonia divide by mitosis, they form these. these then undergo meiosis to form _________ which undergo meiosis II which results in four haploid cells called _______ which then mature into ______. process continues

oogenesis; oogonia; primary oocytes; ovum; polar bodies

formation of the egg. diploid cells called____ divide by mitosis to form ________. the production of the last step stops early in development in many mammals (before birth in humans). when these cells undergo meiosis, only one of the our haploid products (known as ________) matures into an egg. the other cells (called _______) do not mature into egg

gonad

sex organ. male version is testes and female version is ovaries. in the vast majority of animals, gametogensis occurs here.

testes

male gonads. diploid cells here called spermatogonia. highly coiled tubes surrounded by connective tissue. held outside abd cavity in the scrotum where the temp is lower than the abd cavity

ovaries

female gonads

spermatogonia

diploid cells int he male gonads that divide by mitosis (forming primary spermatocytes) to generate the cells that undergo meiosis (producing secondary spermatocytes) which then undergo meiosis II.

primary spermatocytes; secondary spermatocytes; spermatid; sperm

when spermatogonia divide by mitosis, they form these. these then undergo meiosis to form _________ which undergo meiosis II which results in four haploid cells called _______ which then mature into ______. process continues

polar bodies

product of meiosis, three out of four divisions of the oocytes do not become an egg, but they become this.

mating

pairing of the opposite sex (dioecious) or hermaphroditic (monoecious) organisms for copulation

monoecious

hermaphroditic organism

dioecious

oppsite sex organism

simultaneous hermaphrodite

male and female at the same time (ex earthworm)

sequential hermaphrodite

may function as a male or female at different times (ex anemone fish)

copulation

union of sex organs of two sexually reproducing animals for insemination (deliberate introduction of male reproductive cells into female reproductive organs) and subsequent internal fertilization

zygote

the union of egga and sperm creates this single diploid cell which will develop into an embryo

external fertilization

eggs shed by female are fertilized by sperm in the external enviro

internal fertilization

sperm are depositited in or near the female reproductive tract (which requires behavioral interactins and compatible copulatory organs) and fertilization occurs within the tract

fertilization: six steps

fertilization. six steps

1. recog of sperm and egg

2. activation of sperm, enabling it to access plasma membrane of egg (ACROSOMAL PROCESS)

3. plasma mem of egg fuses w/ plasma mem single sperm

4. egg blocks other sperm (CORTICAL REACTION)

5. egg metabolically activated to start dev.

6. egg/sperm nuclei fuse. creates diploid nucleus of zygote

genetic variation

sexual reproduction results in this. potential advantages: increased repro success of parents in changing enviro, increase rate of adaptation, shuffling of genes and elimination of harmful ones. based on ind assort of chromos, crossing over, and random fert

independent assortment of chromosomes

random orientation of homologous pairs of chromosomes in metaphase I. results in 50% change of particular daugher cell of meisos I getting a maternal/paternal chromosome from a particular homologous pair. 2n possible chromosome combinations in gametes.

crossing over

produces recombinant chromosomes that carry alleles from both parents and increase the genetic variability of gametes. produces chiasmata that hold homologous chromosomes together.

random fertilization

defined by the number of possible combinations in zygote = (# of possible combinations in gametes)^2 = 2^n * 2^n= 2^2n

female external reproductive anatomy

two sets of labia (minora and majora), clitoris, vagina

labia (minora and majora)

two sets of this, folds of skin that cover the urethral and vaginal openings.

clitoris

sensitive organ that develops from the same embryonic cells that give rise to the penis in males. has a head called a GLANS covered by the PREPUCE

vagina

chamber where semen is deposited during sexual intercourse and through which a baby is delivered during childbirth

internal female repro sysem

has two functions, production and transport of eggs and development of offspring

production and transport of eggs

note: eggs are produced in the paired ovaries. during ovulation, egg is expelled from ovary and enters oviduct (FALLOPIAN TUBES) where fertilization takes place. fertilized eggs are then transported to uterus.

development of offspring

embryonic development takes place in uterus. developed fetus passes through its opening, the cervix, and into vagina during childbirth

follicles

contained in the ovaries, consist of partially developed egg, called an oocyte, surrounded by support cells

oocyte

partially developed egg contains in the follicles of the ovary. once a month, it develops into an ovum by the process of oogenesis

oogenesis

oocyte developes into an egg whcih is then released into oviduct (FALLOPIAN TUBES) where it can be fertilized

ovulation

when the ovary released a fertilized egg into the fallopian tube

fallopian tube

where the ovary releases the egg to during ovulation so it can be fertilized

oviduct

aka, the fallopian tubes. the egg travels from the ovary to the uterus via this path. cilia here help convey egg to uterus

uterus

organ that holds embryo/fetus as it develops. lined with endometrium which has many blood vessels. narrows at the cervix, which opens into the vagina

Cervix

called "mouth of the womb", the narrow end of the uterus that opens into the vagina

vagina

thin walled chamber that is the repository for sperm during copulation and serves as birth canal. opens to outside at vulva

vulva

outside of the vagina, consists of labia majora/minora and clitoris.

glans, prepuce

head of the clitoris, covered by the ______

spermatogensis and sperm storage, production of accesory fluids, transport and delivery

the reproductive system in human males has just three basic functional components which are?

epididymis

stores the sperm that are produced in the testes

accesory glands

seminal vesicles, prostate gland, and bulbourethral gland are these. provide accesory fluids. semen is a combo of accesory fluid and sperm. accesory fluid varies widely among animals

semen

combination of sperm and accesory fluid

vas deferens

tubes that transport sperm from epididymis to the EJACULATORY DUCT

Ejaculatory duct

Tube through which semen enters the male urethra

urethra

a longer tube that passes through the penis and services both the reproductive and urinay systems in males and is expelled during ejaculation

baculum

some species have this bone inside their penis. not present in humans.

Seminiferous tubules

Narrow, coiled tubules that produce sperm in the testes.

leydig cells

produce hormones and are scattered between the seminiferous tubules of the testes

scrotum

sack that testes are held outside of the animal for lower temp

sperm path

1. from seminiferous tubules of testis, sperm pass into coiled tubules of epididymis

2. during ejac, sperm propelled through muscular vas deferens

3. then ejaculatory duct

4. into urethra

5. exits penis

seminal vesicles (x2)

accesory gland that contribute about 60% of the total volume of semen

prostate gland

accesory gland that secretes its product directly into the urethra through several small ducts

bulbourethral glands

accesory gland that secrete a clear mucus before ejaculation that neutralizes acidic urine remaining in the urethra

penis

composed of three cylinders of spongy erectile tissue. during arousal, tissue fills with blood causing erection. head ofpenis has thinnger skin covering than shaft, more sensitive to stimulation.

spermatogenesis vs oogenesis

1.all four products of meiosis develop into sperm, while only one of four becomes an egg

2.spermato occurs throughout adolescence and adulthood

3. sperm produced continously without prolonged interruptions like oogenesis

spermatogenesis: sperm dev. continous and prolific (millions per day). each 7 weeks to develop. small and motile to

oogenesis: dev of mature egg prolonged process. immature eggs form in female embryo, BUT do not complete dev until yrs or decades later. eggs, much larger than sperm, carry out fuction in female.

3 ways spermatogenesis differs from oogenesis?

hypothalamus, anterior pituitary, gonads

human reproduction is coordinated by hormones from what three places? hormones serve many functions in addition to gamete production, including sexual behavior and the development of primary and secondary sex characteristics

gonadotropin-releasing hormone (GnRH)

secreted by the hypothalamus and directs the release of FSH and LH from anterior pituitary

FSH and LH

regulate processes in the gonads and the production of sex hormones(such as estrogen in females)

remale reproduction cycles. NOTE

Note: hormone secretion/repro events are cyclic. prior to ovulation, endometrium thickens with blood vessels to prep for embryo implantation. if no implant, endo sheds (menstruation). two cycles female repro that hormons link 1, ovarian cycle, 2, menstrual cycle

ovarian cycle

changes in the ovaries started by release of GnRH, FSH, LH stimulating follicular phase ending at ovulation when secondary oocyte is released. then remaining follicular tissue forms CORPUS LUTEUM (LUTEAL PHASE) which disintegrates and ovarian steroid hormones decrease

follicular phase

follicle growth and an increase in the hormone estadiol. this phase ends at ovulation.

luteal phase

follows ovulation, third step of ovarian cycle. follicular tissue left behind transforms into the corpus luteum which disintegrates and ovarian steroid hormones decrease

menstrual cycle

1. thickening of endometrium during the proliferative phase (c. w/ follicular phase)

2. secretion of nutrients during secretory phase (c. w/ luteal phase)

3. shedding of endometrium during menstrual flow phase (c. w/ growth of new ovarian follicles)

new cycle begins if no embryo implants in endo

proliferative phase

part of the menstrual cycle. thickening of the endometrium. coordinates with follicular phase

secretory phase

part of the menstrual cycle. secretin of nutrients. coordinates with luteal phase

menstrual flow phase

part of the menstrual cycle. shedding of the endometrium. coordinates with the growth of new ovarian follicles.

About this deck

By: Aaron Fedor
Textbook:

Campbell Biology (9th Edition)
Study Guide for Campbell Biology
Created: 2012-04-15
Size: 76 flashcards
Views: 6

About StudyBlue

“Simply amazing. The flash cards are smooth, there are many different types of studying tools, and there is a great search engine. I praise you on the awesomeness.”
Dennis