Chapters 11.4, 34.3, 34.4, and 10.4 Flashcards
What is produced by meiosis?
4 haploid cells total
Describe how crossing over increases genetic diversity.
Chromosomes exchange DNA. This creates more unique chromosomes and more genetic diversity.
What happens during metaphase 1 and how is genetic diversity increased?
Spindle fibers move tetrads to the cell equator randomly which increases genetic diversity.
What is the end product after cytokinesis 1?
2 haploid cells
What determines when cytokinesis 1 begins?
The formation of the cleavage furrow
What are the two different cell types?
Somatic and sex cells
Meiosis creates more ______ and ______, while mitosis creates more
egg & sperm, body cells
What is meiosis?
A process in which our gametes (sperm & egg) reproduce
What else is meiosis called? Why?
Reduction division because the number of chromosomes is being cut in half.
What does meiosis 1 alone create?
2 haploid cells
What does interphase 1 start with?
A diploid cell (set of chromosomes from each parent)
What are the three stages of interphase and what happens in each?
G1 period of growth, S DNA replication, G2 organelles copied and preparation for division.
What all happens in prophase 1?
Centrioles begin to create spindle fibers and move to opposite poles, nuclear membrane and nucleolus break down, chromatin coils into chromosomes
What are homologous pairs?
Chromosomes that are the same size, shape, or genetic material
What’s a synapsis and what does it form?
A synapsis is when homologous chroomosomes pair up, forms a tetrad.
What is a tetrad?
4 sister chromosomes
What is crossing over and what does it do?
When homologous chromosomes wrap around each other. It also increases genetic diversity by creating unique chromosomes.
Crossing over is completely _______.
random. ex: yeet, 21
How can you tell the difference between metaphase in mitosis and meiosis?
in mitosis there is one row of chromosomes, in meiosis there are two rows of chromosomes
What happens in anaphase 1 and what is left on both sides after?
pulls the tetrads apart to both sides, one chromosome is left on each side after
What happens in telaphase 1 and what marks the end of it?
Nucleolus and nuclear membrane reform, spindle fibers break apart. Cleavage furrow marks the end of this stage.
What marks the beginning of cytokinesis and what happens in this stage?
Formation of the cleavage furrow. It is the division of the cytoplasm.
What is created after cytokinesis?
2 haploid sex cells
List two major differences between meiosis 1 and 2.
Meiosis 2 normally skips interphase 2 and goes straight to prophase 2, and DNA isn’t copied in meiosis 2
What is meiosis 2 very similar to?
Mitosis
What happens in prophase 2?
Centrioles form spindle fibers, nucleolus and nuclear membrane break down, chromatin coils to form chromosomes.
What happens in metaphase 2?
Spindle fibers move chromosomes to the middle
What happens in anaphase 2?
Spindle fibers pull sister chromatids apart, leaving one chromatid on each side.
What happens in telophase 2 and marks the end of it?
Nucleolus and nuclear membrane break down, spindle fibers break apart. cleavage furrow formation marks the end of this phase.
What marks the beginning of cytokinesis 2?
Cleavage Furrow
What is the end product of cytokinesis 2?
4 haploid gametes with 23 chromosomes
Describe the process for males.
Spermatogenesis; 4 spermatids form
Describe the process for females.
Oogenesis: 1 egg and 3 polar bodies formed, eggs get all of the cytoplasm, and the other 3 polar bodies break down.
How often do females make eggs?
Every 28 days (periods)
Female eggs pause in ____ until a female reaches ___.
Meiosis 1, puberty
What are the four major differences between meiosis and mitosis?
Mitosis: - one cell division - starts and ends with a diploid cell - 2 identical daughter cells form - no tetrad, synapsis, or crossing over Meiosis: - two cell divisions - starts with a diploid cell and ends with haploid cells - 4 genetically diverse offspring form - have tetrads but only in meiosis 1
How do we all start?
We all start the same as a diploid zygote.
What happens around the 7th week of development?
Things begin to change on a cellular level. The gender becomes more noticeable.
What is formed when a sperm fertilizes an egg?
Diploid zygote
What are boy and girl gonads?
testes for boys, ovaries for girls.
What are boy and girl sex hormones?
Testosterone for boys, estrogen for girls.
What are sex hormones?
At certain points of a month the estrogen levels increase to be ready for a pregnancy
During childhood, what produces sex hormones?
gonads and adrenal glands in low levels
Where are the adrenal glands in the body?
Right above each kidney
Do opposite sexes produce small amounts of the opposite sexes hormone?
yes
What happens technically during menstrual cycle?
At certain points of a month the estrogen levels increase to be ready for pregnancy
When do menstrual cycles stop for a while and what happens to her levels during this?
Pregnancy, rise
Why do they monitor estrogen levels in pregnant women?
Because if levels become too low or high there is a risk of having a miscarriage
What happens when your levels are low?
They give you hormone injections to protect from miscarriages
What happens during menopause?
Women stop producing hormones and stop having periods and are no longer able to become pregnant
Where does puberty start?
The brain
What does the pituary gland do?
Produces follicle stimulating hormones FSH and lutenizing hormones LH
What do the previous two hormones promote?
Sexual maturation or puberty
What do the testes do and what is it contained in?
Male reproductive organ, scrotum
What does the inside of the scrotum look like?
Ball of yarn
What does the scrotum do?
Makes sperm
What is the penis and what does it do?
Male reproductive organ that delivers sperm to female.
Label a male and female reproductive diagram.
liv luv breegeraghty, kenparrett, and the rest of the squad
What is the epididymis?
Tube in which the spermatids mature
What is the van deferens?
Tube that carries mature sperm from the epididymis to the urethra
What is the urethra?
Tube that carries both sperm and urine (Never at the same time) out of the body
What cannot happen in the urethra?
sperm and urine passing through at the same time
What do the seminal vesicle and prostate gland do?
Produce seminal fluid, nourishes and protects sperm from acidic female environment
Why can’t females get prostate cancer?
They don’t have prostate glands
Why is the female reproduction system acidic?
To protect against reject sperm, they want to wait for the best one
Describe the three parts of a sperm.
Head: contains DNA and enzymes that allow entry to an egg
Mid-piece: contains energy releasing mitochondria
Tail: flagella, locomotion
List 3 similarities and differences between meiosis and mitosis.
Similarities:
- meiosis and mitosis are cell division processes
- both result in more cells
- both do the same general process (PMAT)
Differences:
- meiosis is in two cell divisions
- meiosis starts with a diploid cell and ends with a haploid while mitosis starts and ends with a diploid cell
-only meiosis involves tetrads
What structures make up the gonads?
Testes and ovaries
Compare how the sex hormone levels change throughout the life of males and females.
In females, the level rises and then pauses until puberty, then it begins to proceed on the cycle having periods monthly until the level goes all the way down to zero during menopause. Boys don’t sperm until puberty and from then on they make it all day erryday for the rest of their lives.
Where are the adrenal glands located and what is their function?
Right above the kidney, produces sex hormones
What diploid structure is formed after fertilization?
Zygote
What are the ovaries?
Reproductive female organs that produce eggs
What is the cervix?
Opening of the uterus
What are ovaries comparable to?
Testes on a male
How big are ovaries?
Almond size
What is the oviduct/fallopian tube?
Organ that carries eggs to the uterus
What is the uterus and what does it’s shape look like?
Hollow muscular organ that acts as the womb. Looks like an upside down pear.
What happens to the uterus during and after a pregnancy?
It swells to hold the baby, and shrivels back down to average size after pregnancy.`
Cervical cancer can only happen in ______.
females
What is the vagina?
Birth canal where baby comes out and penis goes during sex
What is the main difference between the male and female reproductive system?
Male’s systems lie partly outside the body while females are completely inside
What is a zygote?
fertilized egg
What is the seminal fluids purpose?
Provides liquid for sperm to swim in because the only way sperm can move is by swimming and they need something to swim in.
What happens when both ovaries release eggs at the same time near a time when sex occurred?
Twins
What happens when sperm choose which side of the fallopian tube to go on?
If they choose the wrong side they will die over a few days from malnutrition but if they choose the right side they will fertilize the egg.
What happens if the number of chromosomes is not adequate?
Genetic disorders
What is a blastocyst?
Hollow ball with some cells to the side on the inside of it, comes from the zygote
As days go on, where does the blastocyst move and how?
Uterus wall, cilia move it
What happens to a tubal pregnancy?
It must be terminated because the baby doesn’t have enough room to grow.
What happens 6-7 days after fertilization?
The blastocyst attaches to the uterus wall, aka implantation
What happens to the wall of the uterus that causes periods?
It peels off if a blastocyst doesn’t attach to it and it comes out of the vagina
What is implantation?
When the blastocyst attaches to the uterus wall
Why do you not have your period when you’re pregnant?
Because the blastocyst is being fed by the uterus wall so it cannot fall out and cause a period.
What is an embryo?
Developmental stage in which cells become more specialized
What is differentiation?
Process by which cells become specialized
Can cells stay totipotent forever?
no
Once the blastocyst is formed, what do the inner and outer cells differentiate into?
Inner: The embryo
Outer: Tissues that attach embryo to mother
Inner cells that form the embryo are called _____.
Pluripotent
What does totipotent mean?
Cells that can develop into any type of body cell including the extra embryonic membrane or placenta.
What does pluripotent mean?
Still can be many types of body cells but not part of the placenta.
What does multipotent mean?
Adult stem cell groups of cells that differentiate to renew and replace old cells.
What are stem cells?
Unspecialized cells from which differentiated cells develop.
Embryonic stem cells are ______.
pluripotent
What is the potential benefit of stem cells?
Could be used to repair damaged cells and implanting totipotent cells elsewhere in the body to help create more cells.
What is an ethical issue with stem cells?
Must be harvested from a pregnancy which kills the child.
What are the two solutions to this ethical issue?
New techniques are being made up to not harm the embryo and they are trying to reprogram adult stem cells to become pluripotent again, like undifferentiation.
What carries sperm to the urethra?
vas defrens
What protective measures does the female reproductive system use to make sure only the best sperm reaches the egg?
It makes its internal section very acidic to kill all unworthy sperm.
Where does fertilization take place?
In the fallopian tubes, but the embryo develops in the uterus.
What is gastrulation?
Cells that differentiate into three germ layers.
What is the endoderm germ layer?
lining of the organs, becomes organs.
What is the ectoderm germ layer?
Becomes skin and nervous system
What is the mesoderm germ layer?
Forms muscle and the skeletal system
What is neuralation?
The formation of the nervous system
What is the placenta?
Organ that connects mother to the embryo
What is the only organ you can ever regrow?
Placenta
What is the placenta useful for?
Gives baby oxygen, and nutrients, and allows it to get rid of waste.
How is the placenta connected to the baby?
Umbilical cord
What is the amniotic sac?
Membrane that surrounds embryo and contains amniotic fluid.
What is the amniotic fluid’s purpose?
Provides liquid for the sperm to swim in once deposited in the vagina.
What happens during the first trimester?
Major organs and tissues begin to form, baby can move slightly but mother can’t notice.
What happens during the second trimester?
Detectable heart beat, tissues become more specialized and complex, bone replaces cartilage, hair and fingernails form, movement can be felt by the mother.
What happens during the third trimester?
Organs mature, breathing is practiced, child grows, lungs prepare for air, body temperature is regulated, central nervous system is fully developed, baby puts head toward exit of uterus.
What is a breached baby?
When the kid goes out butt first from the mom.
What is the major difference between Interphase 1 and Interphase 2?
Interphase 2 is typically skipped in meiosis.
