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Define the term cell cycle
The life cycle that a cell goes through as it develops and eventually divides
what are somatic cells and gamete cells
body cells and sex cells
what is the central feature of the cell cycle
genetic material is duplicated and passed from the parent cell to a daughter cell.
during what phase of the cell cycle are chromosomes replicated
The S phase. The DNA in the chromatin replicates to create an identical copy of DNA. These two identical chromosomes, called sister chromatids.
in what structures is the genetic information of a cell contained? where are these structures located
DNA (dioxyribonuclieic acid) holds genetic information, located in chromosomes
how many chromosomes are there in the somatic cells of humans
46
what are homologous chromosomes
Homologous chromosomes are chromosomes with the same gene sequence / structural features.
why are the X and Y chromosomes known as sex chromosomes
because they determine the sex of the individual
write a sentence that clearly differentiates the terms diploid and haploid
Diploid full chromosome number, haploid half chromosome number
what are the main phases of the cell cycle? Briefly describe each phase
Growth Stage: Also called interphase it is when the cell carries out its regular metabolic functions and prepares for its next division. There are three phases in interphase: G1, S, and G2. G1 phase: The cell grows quickly, making many new cell molecules (except DNA). S phase: The DNA in the chromatin replicates to create an identical copy of DNA. G2 phase: Lets the cell rebuild its reserves of energy to prepare for division. As well, the cell manufactures proteins and other molecules.
Cell Division: There are two main processes in cell Division: 1. Mitosis, the division of the genetic material and the cell's nucleus. 2. Cytokinesis, the division of the cytoplasm and the organelles into two separate cells. The linked processes of mitosis and cytokinesis have three important functions: Growth, Maintenance, and Repair.
what are the four main phases of mitosis? List the key events that happen to chromosomes in each phase
prophase: chromatin condenses into tightly packed chromosome
metaphase: spindle fibers guide the chromosomes to the equator of the cell. The spindle fibers from opposite poles attach to the centromere of each chromosome.
anaphase: each centromere splits apart and the sister chromatids separate from one another.
telophase: The chromatids unwind into the longer and less visible chromatin. The spindle fibers break down. A nuclear membrane forms around each new set of chromosomes.
what three functions does mitosis serve in your body
repair
maintenance
growth
the somatic cells of a horse have 64 chromosomes, how many diploid how many haploid
64 diploid 32 haploid
describe the two key outcomes of meiosis
reduction division (fewer chromosomes) and recombination (recombination of genetics)
in what ways does meiosis serve a different function than mitosis
meiosis goes through two pmats and for gametes
mitosis goes through one pmat and for somatic
where does meiosis take place
Gonads
distinguish between independent assortment and crossing over
independent assortment is when chromosomes randomly align at the equator during metaphase 1
crossing over is when pieces of chromatids of homologous chromosomes cross over to each other
compare primary and secondary oocyte
Primary oocytes are in the first division stage of meiosis. Secondary oocytes have completed meiosis I, but are halted in meiosis II until fertilization.
compare spermatid and sperm cell
Spermatids are immature and undifferentiated cells formed from spermatogonia during meiosis whereas sperm cells are the mature differentiated cells formed after the process of spermiogenesis.
compare oocyte and polar body
Polar bodies form because the egg cell (oocyte) does not divide evenly. The resulting cells have the same DNA, but one is much smaller, called a polar body
distinguish between asexual reproduction and sexual reproduction
Asexual: less energy, guaranteed offspring,does not have genetic variety
Sexual: more energy, two people, not guaranteed offspring, does have genetic variety
describe the function of each of the following structures in a flowering plant: anther, pollen, stigma, ovule
Anther: Where pollen is stored and produced in plants.
Pollen: Sacs that contain male gametes in plants.
Stigma: A sticky structure that captures pollen in plants
Ovule: Sacs that contain female gametes in plants
distinguish between primary and secondary sex characteristics
primary sex characteristics: characteristics given at birth to determine sex. I.E. penis and vagina
Secondary sex characteristics: characteristics that appear after puberty I.E. breasts in women, facial hair in men
arrange the following structures into the order in which sperm passes through them: vas deferens, urethra, epididymis, seminferous tubules
Seminiferous tubules, epididymis, vas deferens, urethra
name the glands that contributes fluids to semen and list what each contributes
Seminiferous tubules: contains sugar as energy source for sperm
Prostate gland: Alkaline fluid that increases PH in female
Cowpers gland: aids in lubrication and neutralizes acidity in urine in urethra
what are the two main purposes of the gonads in both males and females
producing reproductive cells to continue life
producing sex hormones for the reproductive tract
which structures contribute to the movement of the egg from the ovary to the uterus
fimbriae: hair-follicle cells that sweep the egg down the fallopian tube
oviduct: tube that transports egg to the uterus
give two examples of viral STIs and two examples of bacterial STIs
viral: HIV, HPV
Bacterial: Chlamydia, Gonorrhea
what chromosomes combination results in an offspring that is genetically male and that is genetically female
male: XY
female: XX
what is the significance of the menstrual cycle
The menstrual cycle prepares your body for pregnancy. If you are not pregnant, your hormones send a signal to your uterus to shed its lining. This becomes your period.
what is the function of the corpus luteum
To produce the hormone progesterone and prepares your uterus
explain how the uterine cycle differs from the ovarian cycle
The ovarian cycle controls the production and release of eggs and the cyclic release of estrogen and progesterone. The uterine cycle governs the preparation and maintenance of the lining of the uterus (womb) to receive an embryo.
briefly describe male puberty
Puberty begins when the hypothalamus increases its production of GnRH. GnRH acts on the anterior pituitary gland, causing it to release two different sex hormones: FSH and LH. These hormones cause the testes to begin producing sperm and to release testosterone. Testosterone acts on the development of the sex organs and sexual characteristics.
briefly describe female puberty
Puberty begins when the hypothalamus increases its production of GnRH. This acts on the anterior pituitary to trigger the release of LH and FSH. FSH and LH act on the ovaries to produce the female sex hormones estrogen and progesterone. These hormones stimulate the development of the female secondary sex characteristics and launch a reproductive cycle that will continue until about middle age.
briefly describe the ovarian cycle
Is divided into two stages: the follicular stage and the luteal stage. Begins with an increase of FSH. FSH stimulates a follicle to mature. As the follicle matures, it releases estrogen and progesterone. Increased estrogen levels inhibit the release of FSH. Additionally, increased estrogen levels stimulates a sharp increase in LH which triggers ovulation. Increased LH causes the follicle to develop into a corpus luteum. Corpus luteum secretes progesterone and some estrogen. Increased progesterone and estrogen inhibit FSH and LH production. The corpus luteum will disintegrate, leading to a gradual decrease in progesterone and estrogen. Decrease in progesterone and estrogen causes an increase in FSH, which restarts the cycle.
briefly describe the uterine cycle
Uterine Cycle - When a new follicle matures and releases estrogen, the endometrial wall begins thickening. After ovulation, when the corpus luteum produces progesterone, a more rapid thickening occurs. If fertilization does not occur, estrogen and progesterone drop, and the endometrium breaks down - menstruation. If fertilization does occur, estrogen and progesterone remain high, which maintains the endometrium for the developing fetus.
compare and contrast the effect of testosterone on the male body with effects of estrogen on the female body
testosterone: stimulates the male reproductive tract and growth of sex characteristics
estrogen: stimulates the female reproductive tract and growth of sex characteristics
how does the menstrual cycle contribute to successful human reproduction
prepares egg for fertilization, which would then turn into an embryo. Uterine wall also prepares for implantation, if this does not occur it sheds so that it can restart the process of preparing for pregnancy
predict what would happen to testosterone production in the testes in response to an injection of a large amount of testosterone in an adult male
Increasing the amount of testosterone in a male's body would shut down the release of LH and FSH secretion from the pituitary gland, which would decrease the amount of testosterone and sperm produced within the testes.
summarize two methods for enhancing reproductive potential
artificial insemination: sperm is collected and placed in the vagina
In vitro fertalization: sperm and egg are collected and fertilization takes place on a pitry dish, then embryo is placed in the uterus
surrogacy: another female carries the baby
cryopreservation: sperm or egg are kept at low temperatures to preserve the tissue
superovulation: hormone therapy which causes more than one egg to be released at ovulation
describe three methods of contraception
abstinence, condoms, spermacide, birth control
what is the main difference between the embryonic and fetal periods of development
embryonic: growth and development of important organs/tissues intrtnally
fetal: growth and development of external features to survive the outside world
list three events that must occur for fertilization to take place
Sperm transport - The sperm must be deposited and transported to the site of fertilization.
Egg transport - Ovulation must occur and the egg must be "picked up" by the tube.
Fertilization and embryo development - Union between the sperm and egg must result.
arrange the following in order from youngest to oldest: morula, zygote, blastocyst, gastrula
zygote, morula, blastula, gastrula (,neurula)
what is parturition
the process of giving birth
how many stages of parturition are there? what are they?
dilation
expulsion
placential
describe the role of oxytocin in parturition
oxyticin is released by the pituitary gland which causes contractions of the endometrial lining and the production of prostaglandins, which then causes the cervix to dilate during labor
outline how hormones are involved in lactation and the suckling reflex
When a baby suckles on a mothers nipple it stimulates the pituitary gland to stimulate prolactin and oxytocin which are in the mammary glands. The prolactin in the mammary gland stimulates milk production. The oxytocin in the mammary gland contracts to allow milk let down. This process continues as long as there is suckling.
what are stem cells
Stem cells are unspecialized or undifferentiated cells
what are ethical questions arise from the embryonic stem cell research
Embryonic stem cells come from embryo’s, however in order to get these embryos scientists use in vitro fertilization, however some people believe that this is unethical as it is giving an embryo a chance at life but only for scientific research and then, ultimately, terminating it. Is it actually ethical to do this?
write a definition of genetics
Genetics is the study of genes, genetic variation, and heredity in organisms.
explain how a hybrid plant is different from a true-breeding plant
A true breeding plant is homozygous for its alleles, a hybrid is heterozygous which means it has both dominant and recessive alleles
state the meaning of the terms dominant and recessive
dominant:Trait that is always expressed in spite of the presence or absence of a recessive allele.
recessive: trait that can be carried, but is only expressed when homozygous for the recessive trait
distinguish between the terms gene and allele
Genes - The fundamental unit of inheritance. Section of a chromosome, a piece of DNA, that codes for a particular trait.
Alleles - One of the forms in which a gene can exist. Alternate forms of the same gene. Alleles occupy corresponding positions on homologous chromosomes
distinguish between the terms genotype and phenotype
genotype: the combination of alleles for the genetic makeup
phenotype: the expression of the physical trait
what is a punnett square
A grid used to determine the possible combinations of alleles when two parent generations are crossed. Can be used to predict the genotypes and phenotypes of the offspring.
what does it mean to be homozygous for a trait? how is this different from being heterozygous for a trait?
To have either both dominant alleles or both recessive alleles for a trait. to be heterozygous for a trait means to have one of each allele
explain what incomplete dominance is
When neither allele is dominant, in fact they are equally dominant. They interact to produce a new phenotype, a blending occurs.
explain how codominance is different from incomplete domincance
Codominance and Incomplete dominance are two types of genetic inheritance. Codominance essentially means that no allele can block or mask the expression of the other allele, so both are expressed. On the other hand, incomplete dominance is a condition in which a dominant allele does not completely mask the effects of a recessive allele and so there is a blend.
identify the alleles present in Tt gametes
T = dominant allele
t= recessive allele
identify the alleles present in HH gametes
H= dominant
identify the alleles present in HhTt gametes
H= dominant trait 1
h= recessive trait 1
T= dominant trait 1
t= recessive trait 1
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