science
Terms
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- homozygous
- when an organism has two identical alleles for a given character ex. attached-attached-----homozygous for attached earlobes
- Gene
- A portion of DNA that codes for a given polypeptide chain- protein
- Where does Spermatogenesis occur?
- in the testes
- Where are the ovaries found and what are the two purposes of oogenesis?
- Found in the abdominal cavity and two purposes are: 1) produce egg cells, 2) secrete hormones estrogen and progesterone
- Nondisjunction
- Sometimes during meiosis the chroosomes do not seperate properly, gametes then end up with too many or few chromosomes
- tubal ligation
- cut and tie oviducts (fallopian tubes)
- intrauterine device
- plastic devices of various shapes that are placed in the uterus by physician;they don't know how they work, but somehow prevent implantation of zygote (probably scrape against the walls of uterus) no longer available in the US because of lawsuits against doctors
- Mendel's law of segregation
- when gametes are formed a diploid organism the alleles that control a given trait seperate from each other into different gametes and retain their individuality
- spericidal foams and jellies
- make fagina ore acidic, and kills sperm
- Klinefelter's syndrome
- results when a person has an extra sex chromosome 2x's and a y, 47 total chromosomes: egg had two x chromosomes, individual is tall sterile man, often with lower mental capacity
- Where does Oogenesis occur?
- In the ovaries which are suspended in the abdominal cavity.
- sterilization
- surgical, usually permanant, some recent success in reversing
- Variety is generated into a populations gene pool by and explain each?
- 1) mutations 2) sexual reproduction 3) Migration 4) Size of population, explanations in notes 4/5
- demes
- clusters of genes
- Urethra
- passes through the penis and empties to the outside
- of thousands of seconday oocytes that are formed:
- only 13 are ovulated each year, less than 400 ovulated in a lifetime, the rest disinigrate by age 50.
- Ovulation
- During puberty, the ovaries begin to release 1 secondary oocyte every 28 days.
- What 3 glands is seminal fluid produced by?
- 1)seminal vesicles, 2)prostate, 3) cowper's gland
- Clones
- Many plants can be reproduced asexually to form a number of individuals with exactly the same genotype
- As sperm passes through the vas deferens and urethra what is added to form semen?
- sperm and seminal fluid
- Epididymis
- A coiled tube that lies on the surface of the testes and carries sperm to the vas deferens
- Gonorrhea
- Cause: bacteria, symptoms appear 3-14 days after sex, symptoms obvious only in male (discharge from penis and painful urination) treatment: penicillin but resistant strains more common
- What are the two functional components of the testes and what is the purpose of each?
- Seminiferous tubles (where sperm is produced), and Intersitial cells (secrete hormone, testosterone)
- Herpes
- Over 20 million Americans have genital herpes, 1 in six sexually active people have genital herpes, cause by 2 viruses: Herpes simplex 1- cold sores and painful blisters on lips, Herpes simples virus 2- painful ulcers on genitals (genital herpes) symptoms: appears in 2-20 days. Virus stay in nerve cells while dormant type 1 can cause blindness, type 2 can cause meningitis more in notes
- Who was the first person to systematically study patterns of inheritance and what did he do?
- An austrian monk named Hohann Gregor Mendel, he conducted a series of experiences with ordinary garden peas. The laws he discovered where not accepted until 3 other researchers came up with the same conclusions.
- Mendel's law of dominance
- when an organism is heterozygous for a given trait, the allele that is expressed is said to be dominant: the allele that is over shadowed is said to be recessive
- alleles
- Alternative forms of genes for the same characteristic. ex. red, blonde, brunette
- Hormones
- Chemicals(usually proteins or steroids) produced by one part of the body (usually a gland) that alters the activity of another part of the body called the target organ.
- heterozygous
- An organism that has different alleles for a given characteristic, attached-free
- monoculture
- today many of our most important food crops are planted as a vast field of simular genotypes
- During spermatogenesis the cells lining the seniferous tubules enlarge ad become what?
- primary spermatocytes
- Small vs. Large gene pools
- Small gene pools can result in lowered adaptability to environental changes--may lead to extinction, a large gene pool with a great variety of genes is more likely to contain genes that will allow some of the organisms to survive (DDT and Flies)
- diaphragm
- membranous shield placed over erect penis before intercourse,
- species
- a group of organisms that have the ability to breed and produce fertile offspring. (have the same number and kinds of choromosomes and genes).
- The characteristics of organisms are controlled by?
- Genes
- Recessive allele
- the allele that is masked and does not express itself.
- Population genetics
- The study of why differences in gene frequencies (how often a gene occurs in a population)
- AIDS
- notes 12/12
- luteal phase
- notes
- Populations gene pool
- consists of all the genes of all the organisms in the population, as a result several factors such as geographic barriers or resource availability, the individuals within a population are usually found in clusters that breed with each other.
- monohybrid cross
- A gentic cross in which a single characteristic is followed from one generation to the next.
- Abortion
- termination of zygote, embryo or fetus, 3 methods 1)dilation and curettage (D and C, which is also used to detect cancer), 2) suction devices, 3) injection of saline solution into uterus
- Downs syndrome
- (mongoloidism) occurs when there is an extra chromosome 21. 47 total chromosome in zygote, low level of intelligence, thickened eyelids, faulty speech
- what is the genotype
- The particular combination of alleles (genes) present in a given organism
- genetics
- the study of how genes control these characteristics and how they are passed on form generation to generation (inheritance)
- When does Oogenesis begin?
- Before the female is born
- phenotype
- the way that this combination of genes expresses itself
- flow phase
- notes
- Vas Deferen
- run into the abdominal cavity and joins the urethra just beyond the point where the urethra leaves the bladder.
- Rythym method
- refrian from sex on those days of the month when the secondary oocyte may be present
- Linkage
- Pairs of alleles on nonhomologous chroosomes seperate independently of each other. follows mendel's law of independent assortment
- Gametogenesis
- The production of gametes
- Where are the testes found
- in the scrotum
- Pleiotropy
- Occurs when a gene has more than 1 effect on the phenotype of an organism, occurs often, sometimes one effect is good other bad.
- Follicle
- The secondary Oocyte are incased in this saclike structure
- polygenetic inheritance
- some characteristics are deterined by several pairs of alleles on the same or different chromosomes
- Speromatogenesis
- The production of sperm
- What is polar body 1?
- During cytokenesis one of the two cells formed during meiosis 1 gets less cytoplsm and eventually disinegrates.
- some males release up to ________ per ejaculation?
- 1 billion sperm cells
- Syphilis
- Primary stage: in about 3 weeks a hard painful sore develops on genitals dissapears after a short time, no more symptos for 2-4 months, secondary stage: skin rash and infection of organs may enter latent period which last through life, may enter Tertiary Stage: severe nervous and circulatory system damage and even death. Treatment: penicilin, some resistant strains
- Turner's syndrome
- results when a person has only 1 x chromosome, 45 total chromosomes in zygote: one of the gametes is missing a sex chromosome. individual is female, sterile, short, webbed neck problems with math and spatial relationships
- The small gene pool within a monoculture results in
- 1) the need for herbicides and pesticides to maintain the proper conditions for plant growth (cant breed hybrids resistant to everything) 2) a greater potential for a new disease to wipe out the entire population.
- pill
- progesterone inhibits secretion of fsh and lh from the pituitary thus preventing follicular growth and ovulation
- What did Mendel believe and how was he wrong?
- He thought of a gene as a "particle" that was passed on from parent to offspring, but today we know genes are composed of specific sequences of DNA nucleotides
- vasectomy
- cut and tie vans deferens; sperm remain in testes and are reabsorbed, ejaculation is normal but only contains eminal fluid, new studies indicate it may damage cirulatory syste
- Proteins
- control the characteristics displayed ex. insect-human, blond-brunette
- Gene populations
- All the organisms of a given species found within a specific geographic region
- follicular phase
- notes
- dihybrid cross
- a genetic cross in which a 2 pairs of alleles (2 characteristics) are followed from one generation to the next
- What were the std's that america was worried about and what is now?
- Gonorreah and syphalis used to be, now herpes and AIDS epidemics are of more concern because neither can be cured.
- coitus interruptus
- removal of penis from the vagina prior to ejaculation: sometimes not easy to do
- multiple alleles
- some characteristics are determined by 3 or more different alleles
- probability
- the chance that an event will happen. probability= the number of events that can produce one outcome/ the total number of possible outcomes. examples in notes
- lack of dominance
- in some cases 2 unlike alleles both express themselves
- No two individuals in a deme are exaclty alike, the members of a deme usually resemble each other more closely than members of other demes of the same species because?
- 1) they are more closely related genetially--breed together more often than with members of other demes 2) exposed to more simular environmental influences---selection pressures.
- Gene Frequency
- Usually stated mathematically in terms of how often a particular show up in the gametes of a population. It is possible for two demes to hav ehte same gene poool but different gene frequences. VERY IMPORTANT- gene frequencies have nothing to do with dominant or recessive genes. within a gene recessive is found more often then dominant.
- selective breeding is usually accomplished by
- 1) finding wild demes that are homozygous for the desired trait 2) breed small groups to form organisms that are homozygous for desired traits *note it is hard to breed an individual that is homozygous for 2 good traits
- Demes exist because of
- geographical barriers (mountains, rivers) and environental differences (temp changes with altitude, latitude, light intensity.)
- Mendel's law of independent assortment
- members of one gene pair seperate from each other independently of the members of other gene pairs
- contraception
- prevention of fertilization
- estrous cycle
- the rythic changes in the female reproductive tract
- What are the 4 functions of seminal fluid
- 1) vehicle for transport of sperm 2)lubrication of passages, 3) cheical buffer against acids in female genital tract, 4) contains sugar which provide energy
- How do homozygous genes and heterozygous genes interact?
- often one allele will mask the effect of the other allele for a given trait----dominant allele
- Oogenesis
- The production of eggs