reproduction
what is a phenotype?
appearance, expressed or seen. ex) purple
what is a genotype?
the letters used as symbols for the genes. ex) Pp
what does homozygous mean?
the same thing. (PP)
what does heterozygous mean?
different things (Pp)
what did mendel do for his flower experiment?
he crossed a purple flower (PP) with a white flower (pp) and 100% of the first generation offspring were purple (Pp). for the second generation, he crossed the offspring (Pp) with each other and 75% turned out purple, while 25% was white. this is because the four possibilities were: PP, pp, Pp, Pp.
what is the key defining feature of sexual reproduction?
two parents
where do cells come from?
existing cells.
how are new cells made? (process)
cell division
is cell size limited?
yes
how does a cell get a complete set of instructions?
1/2 comes from the sperm, 1/2 comes from the egg
what is a zygote?
a fertilized egg cell that results from the union of a female and male gamete
why do we need more cells?
grow, healing and tissue repair, maintenance of cells in the body, reproduction
what does a cell need to do before it divides?
must duplicate or make a second copy of all its instructions / chromosomes. that way the parent (og) cell can give a complete set of instructions to each of the daughter cells (new cells)
what are the two stages of cell division?
division phase, interphase.
what are the three parts of interphase?
G1 (gap 1)- rapid cell growth, takes in sugars and proteins. S (dna synthesis)- duplicates chromosomes in nucleus, genetic material is copied. G2 (gap 2)- continues growth, preps for division
what stage do cells spend most of their life in?
interphase, particularly synthesis
what is a chromosome?
parts of a cell that contain instructions (dna)
how many chromosomes does a regular human cell have?
46 chromosomes, 44 autosomes which come in pairs, and 2 sex chromosomes, which specify if someone is male (xy) or female (xx)
what are the pairs of autosomes called?
homologous chromosomes. have all the same genes arranged in the same order. the pairs talk about the same traits. not exactly identical
what are the chromosome copies?
sister chromatids (duplicates), they are identical. until the cell divides, the copies stay connected with each other by their middles (centromeres.
what happens to the sister chromatids when the cell divides?
the copies are pulled apart, and each new cell gets one identical copy of each chromosome
what is the result of mitosis? (cells)
cells with a total of 46 chromosomes. beginning soon after fertilization, all the cells in your body were made this way.
what is the purpose of meiosis? (chromosomes)
to reduce the number of chromosomes by half. to create genetic diversity
what type of cells division do the sperm and egg go through?
meiosis
how does meiosis work? (language)
the cell copies each chromosome. homologous chromosome pairs line up and exchange parts. the newly combined homologous chromosome pairs are divided into two daughter cells. then the sister chromatids are pulled apart into a total of four reproductive cells. each of these cells has one copy each of 23 chromosomes.
how many chromosomes do egg and sperm have?
23 each. they combine to make a zygote with 46 chromosomes.
chromosome pairs (fertilization)
one homologous chromosome came from each parent. they have the same genes arranged in the same order, but there are small variations in the dna letters.
what does mitosis do? (person)
creates a person with an identical set of chromosomes in every cell
what does meiosis do? (cells)
generates reproductive cells wuth new combinations of gene variations
why do cells have to divide? #1 (membrane)
if cells were to increase in size, it would become difficult for the cell to receive nutrients and remove waste. substances can only enter and exit a cell through the cell membrane. The larger the cell, the harder it would need to work to move substances from its centre to its membrane
why do cell have to divide? #2 (nucleus)
the distance from the nucleus to all parts of the cytoplasm becomes larger, making it difficult for the nucleus to monitor and control the activities of the cell. The cell size must be kept small for its efficient operation. Cell growth can only take place by increasing the number of cells.
what is the cell division phase?
small part of the cell cycle that consists of mitosis and cytokinesis.
what is mitosis? (nucleus)
the division of the nucleus in such a way that both cells have a complete set of chromosomes.
what is cytokinesis?
cell division is complete when the cytoplasm is shared between the two cells resulting from the division.
PMAT
prophase, metaphase, anaphase, telophase
prophase (prepare)
you can now see the chromosomes. duplicates attached at the centromere. The strands of DNA coil up to form rope-like structures called chromosomes. the DNA has been copied, so there is a duplicate of each chromosome present. During prophase, the nuclear envelope begins to dissolve and disappear. In animal cells, spindle fibres begin to form and stretch across the cell.
metaphase (line up)
the spindle fibres tug the double-stranded chromosomes into a line across the middle of the cell.
anaphase (split up)
the spindle fibres shorten, pulling the centromere apart, causing the chromosomes to move to opposite poles of the cell.
telophase (cluster up)
the chromosomes are located at opposite ends of the cell. the spindle fibres begin to disappear and a nuclear membrane forms around each new set of chromosomes. chromosomes begin to uncoil and form strands of dna. cytokinesis begins.
cytokinesis after pmat
at this point, there are two sets of nuclei in a single cell. the spindle fibres shorten, causing the double-stranded chromosomes to pull apart. one strand from each double will move to either end of the cell.
what happens before mitosis?
the cell is in interphase, so the cell prepares for division by duping chromosomes in the nucleus
12 parts of a cell
ribosomes, cytoskeleton, cell membrane, golgi apparatus, endoplasmic reticulum, nucleus, mitochondria, lysosome, vesicle, cell wall, vacuole, chloroplasts
what are vesicles?
Small containers that carry materials between cell compartments and out of the cell
what is the cell membrane?
• Protective barrier around the outside of the cell
• Controls what molecules get in and out
• Helps cells communicate with each other
what is the nucleus?
• Stores genetic information in the form of long, stringy
DNA molecules
• This is where genes are copied to make messages
what is the cytoskeleton?
• Long fibers that give a cell shape and structure
• Keeps organelles in place
what is the mitochondria?
• Kidney-shaped with two layers of membrane
• Break down molecules to get energy for the cell
what are ribosomes?
• Small structures that don’t have their own membrane
• Read messages from the nucleus to build proteins
what is the endoplasmic reticulum?
• Smooth ER is where lipids and hormones are made
• Rough ER has ribosomes on it, which build proteins
what is the golgi apparatus?
• Gets packages of proteins from the ER and moves them through a series of stacked compartments
• Adds tags to proteins based on where they need to go in the cell
what is the lysosome?
• Small compartment filled with digestive enzymes
• Breaks down unneeded proteins and damaged cell
parts for recycling
what is the cell wall?
separates the interior contents of the cell from the exterior environment, provides shape, support, and protection
what is a vacuole?
stores food, waste, and water for all
what are chloroplasts?
produce energy through photosynthesis
what are all living things made of?
cells. which are the smallest unit that can be said to be alive
what is the general criteria for being alive?
1. Program — This includes a way to encode instructions for building the life form, a way to read those instructions, and a way to replicate them to make more living things (i.e.,reproduction).
2. Metabolism — Mainly, this is a way to capture and use energy. It can also include building molecules that the life form needs.
3. Container — This is a barrier (i.e., cell membrane) that keeps the life form separate from its environment. Often the container selectively lets things in and out.
trait vs tradition
trait- genentic tradition- choice
relative complexity of an organism. sex v ace
sex- complex organisms tend to reproduce sexually. ace- simple organsims tend to reproduce asexually
# of parents who contribute genetic info to offspring. sex v ace
sex- (meiosis) two parents, unique offspring. ace- (mitosis) one parent, genetic copies/clones
reproductive mechanism sex v ace
sex- gametes from two parents join (sperm and egg), fertilization, meiosis. ace- splitting in half, mitosis, no gametes, come off one parent
relative amount of parental care sex v ace
sex- tend to care more, developing offspring are protected, fewer offspring. ace- little to no care, more offspring, rapid reproduction
genetic variation in offspring sex v ace
sex- only from sexual reproduction, combining from two parents. ace- little to no genentic variation, can have random mutation
what are body cells?
somatic cells (2n)
what does n stand for and how many is there?
n- number of types, we have 23
what is 2n (#)
46, two of each type
what does meiosis achieve (chromosomes)
reducing the chromosome number by half, and not just any half, one of each type, so each sex cell gets one of each chromosome
what is 2n-n
diploid - haploid
how many chromosomes in a gamete?
22 autosomes, 1 sex chromosome
state differences between a somatic cell and a reproductive cell
s- 2n, identical to parent, 1 parent. r- n, different to parent, 2 parents
what would happen to the offspring in sexual reproduction if meiosis did not occur?
double chromosomes
what are the two stages of meiosis
meiosis 1 (reduction) meiosis 2 (division)
how many daughter cells does one parent cell produce during meiosis?
four
name all 11 parts of the male reproductive system
scrotum, epididymis, vas deferens, prostate gland, seminal vesicle, urethra, testes, seminiferous tubules, urinary bladder, cowpers gland, penis
scrotum
a pouch of skin that regulates the temperature of the testes by raising or lowering them
epididymis
a long, crooked duct on the testes where sperm are stored, located in the scrotum
vas deferens
the duct that carries sperm from the epididymis to the ejaculatory duct and urethra; the tube connecting the testes to the urethra
prostate gland
a gland located near and that empties into the urethra, which produces a secretion that improves sperm viability
seminal vesicle
glands that contribute fructose to sperm, the fructose serves as an energy source
urethra
a narrow tube that transports urine from the bladder to the outside of the body, in males, it also conducts sperm and semen to the outside
testes + seminiferous tubules
the male gonads that produce sperm and male sex hormones, they are paired organs that contain seminiferous tubules in which sperm are produced
parts of a sperm
head and tail, the head contains the genetic material. the tail provides the mobility the sperm needs to travel to the egg.
what happens when sperms leave the seminiferous tubules?
they are stored in the epididymis until they leave the body
which glands produce semen
cowpers gland, prostate gland, and seminal vesicles. they are to help move the sperm
where does the vas deferens lead
to the urethra where semen can travel through the penis into the female
what happens to males during puberty (hormones)
the brain produces sex hormones called androgens. the part of the brain responsible for this is the hypothalamus, which releases a hormone to the pituitary gland, which releases two hormones: lutenizing hormone and follicle stimulating hormone
what does LH do (males)
travels to the testes and produces testosterone
what does testosterone do
onest of sperm production, sexual organs grow and develop, voice changes, muscle and bone grow. FSH combines with T to produce more sperm
name all 10 parts of the female reproductive system
uterus, cervix, rectum, vagina, urethra, urinary bladder, ovary, oviduct, ureter, endometrium
vagina
the tube shaped part of the FR system that recieves sperm from the male and acts as the birth canal
cervix
connects the vagina to the uterus
uterus
the location where the fertilized egg will travel. in the uterus, the fertilized egg will recieve nourishment and protection as it develops. where the zygote develops into an embryo
ovary
the primary FR organ. the place where a follicle cell will develop into a mature egg cell that is ready to be fertilized with sperm. produces egg cells
oviduct
the tube connecting the ovaries to the uterus. after a primary oocyte has travelled through the oviduct to the uterus, it will be a mature egg that is ready to be fertilized.
follicle
the ovary contains many follicles composed of a developing egg surrounded by an outer layer of follicle cells.
egg cell formation and what happens to it
the follicle produces an egg cell that breaks through the ovary wall to deposit a mature egg cell into the oviduct. this process is calld ovulation. the corpus luteum remains in the ovary, ready to form hormones if a pregnancy begins. if the egg is not fertilized, the corpus luteum disappears in about ten days. the egg can survive for 1-2 days, which is when fertilization can occur
where does fertilization occur
in the oviduct. the sperm move through the vagina, cervix, uterus, and into the oviduct.
endometrium
the lining of the uterus. provides nourishment to the developing embryo
when do women have all the egg cells she will ever have?
in her mothers womb
what happens after fertilization (reproductive system)
the fertilized egg is moved into the uterus
what happens during the menstrual cycle
building up the endometrium (follicular phase), ovulation, prepping hormonally for pregnancy (luteal phase), shedding the endometrium if no pregnancy occurs (menstrual phase)