Development part 1 (quiz 4) Flashcards
What is the definition of development?
the gradual modification of anatomical structures and physiological characteristics from fertilization to maturity
development starts at fertilization and ends at….
maturity
What stages are included in prenatal development?
embryological and fetal development
When does embryological development occur?
during first 2 months after fertilization
What is the study of embryological development called?
embryology
When does fetal development begin?
at the start of 9 weeks (in the womb) and continues until birth
What is postnatal development?
-commences at birth
-continues to maturity when aging process begins
Both the genetic material inherited from parents (_____________) and normal development in the uterus (__________________) play important roles in determining the homeostasis of a developing embryo and fetus and the subsequent birth of a healthy child
heredity, environment
Sexual reproduction is the process by which organisms produce offspring by producing sex cells called…
gametes
What are male gametes called?
sperm
What are female gametes called?
secondary oocytes
What are the organs that produce gametes called?
gonads (only organ/location that can have meiosis)
What are the 2 types of cell division?
mitosis (somatic) and meiosis (reproductive)
During mitosis, a parent cell divides and each of the 2 daughter cells received a chromosomal set ___________ to that of the parent cell. The chromosomes are replicated during ____ phase and are distributed to the daughter cells. The long period between each round of mitoses (the G1, S, and G2 phases) is also commonly called _________________
identical, S, interphase
How many pairs of chromosomes are there before, during and after mitosis?
23 pairs of chromosomes double to 46 during mitosis and then the cells divide, and will have 23 pairs in each cell
What signal happens before mitosis begins?
synthesis- to copy DNA
The cell for most of its life is in which phase?
interphase
What are the 6 phases of mitosis?
1) interphase
2) prophase
3) metaphase
4) anaphase
5) telophase
6) cytokinesis
What happens in prophase of mitosis?
-“get ready”
-build spindle fibers with microtubules and centrioles
-need to get rid of nuclear envelope to “set DNA free”
What happens in metaphase of mitosis?
-m for middle phase
-all chromosomes will line up on the spindles in the middle with its homolog chromosome (ex: chromosome 2 lines up with chromosome 2)
What happens in anaphase of mitosis?
-a for active/apart phase
-chromosomes will move apart from the center and meet at their chosen spindle (move towards opposite poles, ex: chromosome 2 will move to south pole and the other chromosome 2 will move to north pole)
What happens in telophase of mitosis?
-starts when chromosomes are in a clump at their designated poles (keep them trapped in place so cell can divide)
-breakdown spindle fibers, build 2 nuclear envelopes, cleavage furrow forms when membrane get pulled in
What happens in cytokinesis of mitosis?
cells split apart and there are now 2 identical daughter cells
Meiosis takes __________ cells to form _______________ cells
diploid, haploid (gametes)
A single diploid starting cell undergoes meiosis I and II to produce ______ haploid gametes that are genetically different from the starting cell that produced them
4
When does crossing over occur?
prophase I (crossing over is with sister chromatids)
What are tetrads?
tetrads are formed by synapses of sister chromatids of homologous chromosomes in prophase I (tetrads are 4 of each chromosome)
When is DNA copied in meiosis?
BEFORE meiosis I
Is DNA copied before meiosis II?
NO
How does meiosis differ from mitosis?
Why do we need meiosis?
sexual reproduction, fertilization, and normal cell functions
Where does meiosis take place?
inside the testes and ovaries
What does meiosis generate?
gametes
What is spermatogenesis? Where does it begin?
-process of sperm production
-begins at the outermost cell layer within seminiferous tubules (within testicles)
What are the 5 cells of spermatogenesis?
1) spermatogonia
2) primary spermatocytes
3) secondary spermatocytes
4) spermatids
5) spermatozoa
What are spermatogonia?
-stem cells that divide by mitosis to produce 2 daughter cells
-one cell remains as spermatogonium (for self-renewal)
-and the other differentiates into primary spermatocyte
What are primary spermatocytes?
cells that begin meiosis I and form secondary spermatocytes for meiosis II
What are secondary spermatocytes?
cells that differentiate into spermatids (immature gametes) during meiosis II
What are spermatids?
immature gamete cells that differentiate into spermatozoa
What are spermatozoa?
cells that lose contact with the wall of seminiferous tubule or the testes and enters fluid in the lumen
fill in the blanks:
2, 4
Spermatogenesis involves 3 integrated processes. What are they?
-mitosis (to not run out of cells, specifically spermatogonia)
-meiosis (to produce gametes/haploid cells)
-spermiogenesis (shape change to lose cell-cell contact)
Mitosis is a part of __________ cell division that produces ______________ daughter cells. Both have identical pairs of chromosomes
somatic, 2 diploid
Gametes contain _________________, half of the normal amount (HAPLOID)
23 chromosomes (NOT PAIRS)
Fusion of male and female gametes produces a __________ with _______ chromosomes
zygote, 46
In a male, spermatogenesis only occurs in the testes within the seminiferous tubules. The process begins with primary spermatocytes and produces….
Secondary spermatocytes > spermatids
The formation of gametes in the ovaries is termed….
oogenesis
When does spermatogenesis begin in males compared to oogenesis in females?
spermatogenesis beings at puberty
oogenesis begins before birth
note: oogenesis occurs in essentially the same manner as spermatogenesis, where meiosis takes place and the resulting germ cells undergo maturation
During early fetal development, primordial (primitive) ________ cells migrate to the ovaries where they will differentiate into ________
germ, oogonia
What are oogonia?
diploid (2n) stem cells that divide mitotically to produce millions of germ cells
Some oogonia develop into larger calls called ________________ that enter prophase of meiosis I during fetal development but do not complete the phase until after puberty. During the arrested stage of development, each primary oocyte is surrounded by a single layer of flat follicular cells, and the entire structure is called a ______________________________
primary oocytes, primordial ovarian follicle
Each month after puberty until menopause, a primordial ovarian follicle will develop into a __________ ovarian follicle and then a ______________ ovarian follicle
primary, secondary
Each month after puberty until menopause, a primordial ovarian follicle will develop into a primary ovarian follicle and then a secondary ovarian follicle. The secondary ovarian follicle becomes larger turning into a tertiary ovarian follicle. Within the follicle, the __________ primary oocyte completes meiosis I, producing _____________ cells of unequal size, each with 23 chromosomes. The smaller cell produced by meiosis I is called the __________________ and is discarded. The larger cell is the secondary oocyte, once formed it begins meiosis II but then stops in ______________. The tertiary follicle soon ruptures and releases its secondary oocyte, a process known as ovulation
diploid, 2 haploid (n), first polar body, metaphase
What hormone triggers the follicle? What does it do?
FSH (follicle-stimulating hormone)
-allows follicle to get bigger and protect the oocyte inside
Which follicle releases a lot of estrogen? What is this a signal for?
tertiary ovarian follicle releases a lot of estrogen
this is a signal for the pituitary gland to release LH (luteinizing hormone)
LH is a chemical messenger that sends message to the tertiary follicle to go to the surface of the ovary, fuse with the ovary wall, and pop out the oocyte, this is called ovulation
What happens after the oocyte is released?
follicle is still in the ovary and will be recycled to corpus luteum, which is a progesterone producing factory
Primary oocyte goes through meiosis I and makes 2 cells. What are they?
primary oocyte will transition into a secondary oocyte and the second cell is called a polar body
the secondary oocyte undergoes meiosis II
Does the secondary oocyte fully go through meiosis II?
no!
will not complete meiosis II until it is in contact with the head of the sperm
SO, there will be only 1 gamete after oogenesis, not 4 gametes like in spermatogenesis
Where are ovarian follicles found?
in the stroma of the ovaries
When are oocytes suspended?
prophase I
FSH is the signal to continue meiosis I during puberty
If the follicle responds to the FSH signal then they will get more complicated and bigger by taking up what?
follicular fluid to help with nutrition (which will end up in the space called the antrum)
and the cells around the follicle will increase in number and release estrogen
What hormone causes ovulation?
LH
Which cell is ovulated?
secondary oocyte (during meiosis II)
During fertilization, genetic material from a sperm and a secondary oocyte merge to form a….
single diploid nucleus
