BIO MIDTERM REVIEW QUESTIONS

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

1. repair

2. maintenance

3. 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

1. producing reproductive cells to continue life

2. 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?

1. dilation

2. expulsion

3. 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