62 Cards in this Set
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Chromatin
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The DNA and protein components of chromosomes, visible as clumps or threads in nuclei.
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Homologous Chromosomes
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Chromosomes that physically associate (pair) during meiosis. Homologous chromosomes have identical gene loci. (One of these is from mom, one is from dad. They are homologous because they have the same gene loci.)
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Random Assortment
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The result of meiosis I that puts random combinations of maternal and paternal chromosomes into gametes. This happens in metaphase I when the homologous chromosome pairs line up at the equator.
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Spermatogonia
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Mitotically active cells in the gonads of males that give rise to the primary spermatocytes. Pre-spermatocytes hanging out in the gonads.
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Spermatids
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The four haploid cells produced by meiotic division of a primary spermatocyte.
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Oogonia
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Cells that produce primary oocytes by mitotic division. Pre-oocytes that hang out and wait to become oocytes.
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Oocyte
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A cell from which an ovum develops by meiosis. (Oogonium >(mitosis)> primary ______ >(meiosis I)> secondary ______ >(meiosis II)> polar bodies + ovum.
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Ovum
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The haploid cell produced by meiosis that becomes the functional gamete.
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Polar Bodies
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Cells produced in the first and second meiotic division in female meiosis that contain little cytoplasm and will not function as gametes.
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Gene
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The fundamental unit of heredity and the basic structural and functional unit of genetics.
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Carbohydrates
Examples: sugars, glycogen, starches.
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Function: structural components of cells, energy sources for cell, help give cellular identity.
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Lipids
Examples: fats and oils, phospholipids, and steroids.
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Function: structural components of membranes, sometimes serve as energy reserves, some are hormones and vitamins.
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Nucleic Acids
Examples: DNA, RNA
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Function: storage, transmission of genetic information.
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Nucleolus
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Produces ribosomes.
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Rough endoplasmic reticulum
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Site for protein synthesis for intracellular and extracellular use.
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Ribosomes
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Aids in production of proteins.
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Golgi complex
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Sorts, chemically modifies, and packages proteins produced on the RER.
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Secretory vesicles
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Stores protein hormones or enzymes in the cytoplasm, awaiting a signal for its release.
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Lysosome
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Combines with food vacuoles and digests materials engulfed by cells.
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Mitochondria
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Completes the breakdown of glucose producing ATP.
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Hayflick Limit
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Cells can divide about 50 times
Adult cells: 10-30 times
Embryonic stem cells: unlimited
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G1 of interphase
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Stage begins immediately after mitosis. RNA, proteins, cell increases in size, and organelles are synthesized. Chromosomes are unduplicated.
Time frame: 11 hours
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S of interphase
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DNA is replicated, and chromosomes form sister chromatids.
Time frame: 8 hours
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G2 of interphase
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Mitochondria divide. Precursors of spindle fibers are synthesized.
Time frame: 4 hours
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M phase (Mitosis)
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Form of cell division that produces two cells, each of which has the same complement of chromosomes as the parent cell.
Prophase>Metaphase>Anaphase>Telophase
Time frame: 1 hour
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Cytokinesis
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The process of cytoplasmic division that accompanies cell division.
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Prophase
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Chromosomes condense
Nuclear membrane breaks down, nucleolis disappears
Centrioles divide and migrate to opposite poles of the dividing cell
Spindle fibers form and attach to chromosomes
Centrioles move to opposite poles
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Metaphase
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Chromosomes line up on the midline of the dividing cell
Spindle fibers attach to centromeres
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Anaphase
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Chromosomes are pulled apart by the spindle fibers
Daughter chromosomes begin to migrate to opposite poles
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Telophase
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Cytoplasmic division begins
Disintegration of spindle fibers
Reformation of nuclear membrane and nucleoli
Chromosomes decondense
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Diploid
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2n = 46 chromosomes
(23 from mom, 23 from dad)
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Haploid
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n = 23 chromosomes total
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Spermatogenesis time frame
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Spermatogonium >16 days> primary spermatocyte >16 days> secondary spermatocyte >16 days> spermatid >16 days> mature sperm. Total time: 64 days.
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Oogenesis time frame
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Oogonium forms 2-3 months after conception
Primary oocyte forms 2-3 months after gestation. Remains in meiosis I until ovulation, 12-50 years after formation.
Ootid forms in less than 1 day when fertilization occurs
Mature egg-zygote total time: 12-50 years
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Spermatogenesis
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Spermatogonium > primary spermatocyte > secondary spermatocyte > spermatid > mature sperm.
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Oogenesis
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Oogonium > primary oocyte > secondary oocyte > ootid
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Mendel's law of segregation
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Allele pairs separate during gamete formation.
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Mendel's law of independent assortment
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Alleles of one gene pair segregate into gametes independently of the alleles belonging to other gene pairs. resulting in the production of gametes containing all combinations of alleles.
Just because you get a G doesn't mean you'll get an S instead of an s.
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Cystic fibrosis
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Autosomal recessive
Pleiotropy: mucus buildup everywhere causes multiple effects
Normal at birth, shortened life, usually sterile
1500+ mutant alleles: allelic hetergeneity
1 in 25 people carry allele
Carriers are less likely to die from cholera
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Marfan syndrome
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Autosomal dominant
Pleiotropy: affects skeletal system, eyes, cardio system-- weak connective tissue
Gene codes for component of connective tissue
Tall, thin, long appendages
High mutation rate, 25% are new mutations
Causes aorta to expand and eventually tear
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Hemochomatosis
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Autosomal recessive, common
Better absorption of iron, too much iron is toxic
Pleiotropy: body stores excess iron in many places including muscles and skin
Incomplete penetrance: a lot of people never get enough iron to express symptoms
Most common symptom = joint pain, tiredness
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Familial hypercholesterolemia
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Autosomal dominant (incomplete dominance, but homozygous dominant don't live past 10 or 20).
Too much cholesterol
Heart attacks/strokes in 30s
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OMIM
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Online Mendelian Inheritance in Man
Contains info about human genetic disorders
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Huntington Disease
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Autosomal dominant
Symptoms don't develop until 30-50 years, die 5-15 years after symptoms
Jerky movements, neurodegenerative symptoms
Affected individuals have usually already had kids
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Color blindness
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X linked recessive
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Duchenne muscular dystrophy
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X Linked recessive
Pleiotropy: protein that helps hold muscle fibers together eliminated, muscle loss and mild mental retardation
Mostly new mutations; large gene
Mostly affects males (would have to get two new mutations for a girl, males do not generally reproduce which increases the …
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Becker muscular dystrophy
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X linked recessive
Milder form of Duchenne
Protein that holds muscle fibers is ALTERED, not eliminated
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Penetrance
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The probability that a disease phenotype will appear when a disease-related genotype is present
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Expressivity
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The range of phenotypes resulting from a given genotype
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Camtodactyly
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Dominant, bent unmovable little finger
Example of variable expressivity
Some people have two bent fingers, some people only have one, some don't have any but still have the gene
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Sex-influenced traits
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Autosomal, dominant in one sex, recessive in the other
Ex: Pattern baldness
expressed in males more than in females
Usually due to hormones interacting with DNA
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Sex-limited traits
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Inherited by both males and females, but expressed in only one sex
Ex: genes that deal with breast development in females, or facial hair development in males
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Incomplete dominance
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Flower color in snapdragons
THREE phenotypes: red, white, and intermediate (pink)
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Codominance
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MN blood types
THREE phenotypes
Full phenotypic expression of both alleles in heterozygotes
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ABO blood transfusions
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A can give to A and AB
B can give to B and AB
A, B, or AB can give to AB
O can give to A, B, AB, and O
This is because each RBC has antigens on its surface and unknown antigens will not be accepted, they will be destroyed.
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Mendel's three conclusions
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Genes occur in pairs
Members of a gene pair separate from each other during meiosis
Members of one gene pair independently assort from other gene pairs during meiosis
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Hemizygous
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X linked traits
Males cannot be homozygous or heterozygous
Instead, they are hemizygous for all genes on X chromosome
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Epistasis
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The action of one gene masks or prevents the expression of another gene
Ex: Fruit fly with a gene for red eyes and an unrelated gene for no eyes will not express the red eye gene. Because it has no eyes.
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Phenocopy
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Phenotype that looks like another phenotype, but has a different cause
Ex: Ricketts is caused by environmental factors (Calcium/vitamin D deficiency) but the symptoms are also caused by hypophosphatemia
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Hemophilia
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X linked recessive
Defects in blood clotting
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Preventing HDN
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Mothers given Rh antibody preparation (RhoGam)
during first pregnancy or after miscarriage if fetus is +
Injected Rh antibodies destroy Rh+ fetal cells that enter mother's circulation
must be administered before mother's immune system makes antibodies against +
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Lyonization
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Inactivation of one X chromosome in one cell (females)
Ex: Calico and tortoise shell cats.
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ZOL 141: Exam One (Chap. 1 - 4)