Exam 3 Flashcards
Chromatin
Less coiled DNA, accessible to enzymes and considered to be in an active state
Homologous chromosome
A chromosome which has undergone replication in the S phase of interphase, before mitosis or meiosis begins and looks like an X
Sister chromatid
Each half of a replicated chromosome
Interphase
The stage of the cell cycle where the cell spends most of it’s time, and undergoes normal life and produces organelles
Mitosis
One 2n cell produces 2 - 2n daughter cells.
All living things can undergo mitosis.
Only egg and sperm cells do not undergo mitosis.
There is one cell division event in mitosis.
Prophase
Chromosomes begin to condense and the nuclear envelope dissolves
Metaphase
Chromosomes attach to the spindle fibers and align at the equator or metaphase plate of the cell
Anaphase
Sister chromatids seperates and begin to move to opposite poles of the cell
Telophase
Chromatids are at the poles of the cell, a nuclear envelope reforms around the Chromosomes, and the cytoplasm is about to divide in cytokinesis
Chromosome
Highly coiled DNA seen only during cell division
Somatic cells
Normal body cells with a diploid or 2n chromosome number
Gametes
Egg or sperm with a haploid or 1n chromosome number
Meiosis
Cuts the chromosome number in half.
For example, if a stem cell has 20 chromosomes at the beginning of meiosis 1, the resulting 4 daughter cells will each have 10 chromosomes.
Genetic variability
Is increased by crossing over, sexual reproduction with two different parents, independent assortment, and occasional mutation.
Reduces genetic variability
Cloning or parthenogenesis (one parent with both sex organs producing offspring, I.e. Lizards, some snakes)
Cleavage
The fertilized egg cell or zygote begins to divide
Grastriculation
3 germ layers form.
Ectoderm, endoderm, mesoderm
Neurulation
The neural tube forms which will become the spinal cord. The notochord forms and becomes the spinal cord.
Organogenesis
The organs undergo formation and differentiation when they become functional.
Acrosomal enzymes
And actin fibers in the head of the sperm aid penetration of the sperm into the egg cell of ovum during fertilization.
Cowper’s gland or bulbourethral gland
Produces a mucus like lubricating substance in the male
Bartholin’s gland
A gland in the female which produces a mucus like lubricating substance
Prostate gland
Produces a milky white, alkaline (pH basic) fluid which increases the pH of the vagina and helps improve the chance of sperm living
Scrotum
Tissue sac which houses the testes
Epididymis
Highly coiled tube which stores the developing sperm
Seminiferous tubules
Tubule with sperm cells in the wall. Site of actual sperm production.
Vas deferens
The tube which transports sperm and seminal fluid from the region of the testes to the beginning of the urethra.
Penis
Male organ used for sperm transfer and urination
Uterus
A thick-walled, narrow organ which nourishes the embryo during development
Endometrium
The lining of e uterus
Cervix
Muscular base of the uterus. Produces secretions and closes the uterus.
Graffian follicle
One follicle per ovary which will produce a ripe egg cell or ovum
Follicular cells…
Of the ovary are converted to corpus leuteum after the 14th day of the cycle and begin to produce estrogen on about the 21st day of the cycle.
Ovulation
Occurs on the 14th day of the cycle of a women is on a 28 day cycle.
If pregnancy occurs, progesterone maintains the uterine lining during pregnancy.
Estrogen
Increases the thickness of the uterine lining before ovulation.
Barr bodies
Are highly coiled, tuned off X chromosomes found only in females. One X functions in a female, the other doesn’t. Males have a functioning X and Y chromosome.
An inactive X chromosome. Only found in females and only one in females. If they have a genetic defect, they may have two.
Genital herpes
Caused by the herpes simplex type 2 virus. Cold sore like lesions form of the labia and penis, and can be treated with medication, but cannot be cured, and are highly contagious.
Genital warts
Are caused by a papaloma virus, can be surgically removed, but will return as the virus remains in the skin of the effected area. The warts are contagious.
Syphilis
An old disease caused by bacterium. Some strains of the bacteria are antibiotic resistant. The disease stars with a chancer or raised edge, red, oozy sore. A body rash develops next, followed years later by circulatory and nervous disorders.
Gonorrhea
Another old bacterial disease. This one causes painful urination in men, and pelvic inflammatory disease in women.
Chlamydia
This disease is caused by a tiny parasitic bacterium which cannot produce it’s own ATP. It causes pelvic inflammatory disease in females, eye and lung infections in newborns who’s mother is infected.
Gene
A segment of DNA on a chromosome coding for one trait or protein.
Homologous
Two of the same alleles.
I.e. RR or rr
Heterozygous
Two different alleles.
I.e. Rr
Allele
An alternate form of a gene. R and r are two examples of alleles for flower color
Genotype
The actual alleles in an individual
Phenotype
The results of the genotype, or what you see.
Brown eyes would be a phenotype.
Locus
The location of a gene on a chromosome
Monohybrid cross
A Punnet square looking at one trait.
I.e. Rr X Rr
Dihybrid cross
A test cross looking at two traits.
I.e. Green smooth, green wrinkled, yellow smooth, yellow wrinkled seeds in peas
Sex linked
A trait carried on the X chromosome. More males than females are effected.
Pleiotrophic
One gene effects the expression of another gene.
I.e. Fur color in mice.
One gene codes for color or no color, the other codes for brown or black.
Incomplete dominance
3 phenotypes are seen, and the third phenotype is a blend of the two extremes.
I.e. SS normal RBC, Ss sickle cell trait, ss sickle cell anemia
Thomas Hunt Morgan
Studied fruit flies and crossing over in their chromosomes. He was able to determine:
Which genes were linked.
Construct a genetic map of the chromosome.
Calculate the probability of a cross over event.
Define the centimorgan as a measure of crossover frequency on a genetic map.
Down syndrome
3 copies of chromosome # 21, mental retardation, etc…
Huntington disease
Autosomal dominant, strikes in midlife, metal and physical decline resulting in death.
Neurofibromatosis
Causes skin patches and benign tumors in the skin.
Cri du Chat
A deletion disorder which causes mental retardation, a m,on shaped face, and a high pitched cry like a cat.
Tay Sach’s disease
An autosomal recessive disease which causes an accumulation of glycosphingo lipids and eventual death of a child.
Kleinfelter’s syndrome
XXY male who does not produce sperm and may have some breast development.
Turner’s syndrome
Xo genotype females who is short and doesn’t produce eggs
Cystic fibrosis
Autosomal recessive disorder which produces thick mucus in the lungs and intestines due to a faulty ion channel or transport pore in lung and intestine tissue.
Phenylketonuria
Individual cannot digest phenylalanine and produces black urine. The condition can cause mental retardation.
Sister chromatids
Can cross over, but you will not see the results of the cross.
Nonsister chromatids
Cross over, and you will see the increased genetic variability
True breeding
Situation where a white flower plant will produce another white flower plant.
Syntenic
3 or more genes on the same chromosome
Proto oncogenes
Genes which promote uncontrolled cell growth and division, resulting in a tumor or cancer.
Platelet-derived growth factor
This chemical is released from platelets, and promotes the division of cells at the point of injury. Tissue cells divide and repair the injury site.
Epidermal growth factor
A growth factor which division no growth of epidermal tissue
Erythropoietin
A growth factor released from the kidneys, which quickens the maturation of red blood cells
Tumor suppressor genes
Maintain the cell cycle, and do not promote cell division
Chisma
Crossing over.
Mechanism that promotes genetic diversity.
Independent assortment
Chromosomes randomly moving into daughter cells.
Mechanism that promotes genetic diversity.
Symaptonemal complex
When homologous chromosomes align at the metaphase plate in meiosis 1. This complex could promote crossing over.
Mechanism that promotes genetic diversity.
Parthenogenesis
I.e. Reptiles. When a female fertilizes her own eggs, resulting in no genetic diversity.
Sertoli cells or nurse cells and the production of sperm
They are found in the wall of the seminiferous tubule.
They nurse developing sperm cells.
They secrete nutrients and molecules necessary for sperm production.
They convert spermatids into spermatozoa by engulfing their extra cytoplasm.
The corpus leuteum
Of the follicle begins to produce estrogen shortly after the 21st day of the cycle. This secretion inhibits LH and FSH secretion and triggers the atrophy of the corpus leuteum.
Hybridization
Pollinating by hand with a paint brush or Q-tip.
What Mendal did with the pea plants. Pollinating them by hand.
Cross pollination
Pollination done naturally by the wind or insects. They d not select for any particular trait.
Self fertilization
All tall anthers of a plant drop pollen directly on their stigma of the same plant.
