Download Study Guide for Exam 3 Dr. Osborne

Study Guide for Exam 3
Dr. Osborne
1.
Cell Division and Related Topics
A.
Mitosis
1.
General Considerations
a.
Division of the nucleus as part ofnonnal cell division in somatic cells
b.
Mitosis is part of the cell cycle (GI' S, G2 , Cell Division)
c.
Mitosis is accompanied by cytokinesis which is cytoplasmic division
i.
plant cells do not use centrioles but make a middle lamella
ii.
animal cells use centrioles and pinch apart
2.
Phases
a.
Interphase--part of cell cycle--found between divisions, new chromatids are synthesized
b.
Prophase--chromosomes shorten and thicken. each has two chromatids
.
c.
Metaphase--chromosomes line up in middle of cell
d.
Anaphase--chromatids separate and move apart, each has one chromatid
e.
Telophase--chromosomes lengthen, nuclei are reconstructed
3.
Results
a.
Each daughter cell is identical to the mother cell, diploid cells result
b.
Humans have 22 pairs of autosomes and one pair of sex chromosomes in each cell
B.
Meiosis
1.
General considerations
a.
Meiosis is used only in the fonnation of gametes (reproductive cells)
b.
Gametes have only one of each chromosome
b.
Fonnation of gametes is called 'reduction division' because haploid cells result
2.
Divisions of meiosis
a.
Division I is the separation of chromosome pairs
b.
Interkinesis is between the divisions, its length varies
c.
Division II is the separation of chromatids
3.
Results
a.
Four daughter cells result from each mother cell
b.
The mother cell is diploid, the daughter cells are haploid
c.
The diploid number is restored by the process of fertilization
4.
Oogenesis
a.
Oogenesis is production of egg cells
b.
Meiosis produces four nuclei, three are discarded
c.
Result is one haploid egg cell with all of the cytoplasm
5.
Spennatogenesis
a.
Spennatogenesis is production of spenn cells
b.
Meiosis produces four cells which become spenns
c.
Result is four haploid sperm cells; some male, some female
C.
Reproduction
1.
Female reproductive system
a.
Ovaries produce the egg cells by meiosis
b.
After ovulation the egg cell travels through the oviduct
c.
Fertilization results in the restored diploid number of chromosomes
2.
Male reproductive system
a.
Testes produce male and female spenn cells by meiosis
b.
Spenn cells leave the body via the vas deferens and urethra--they enter the vagina
c.
A single spenn cell will fertilize an egg in the oviduct
3.
Fertilization
a.
Fertilization restores the 2n number. The spenn and egg are each n.
b.
After fertilization the embryo begins to develop
Study Guide for Exam 3
Dr. Osborne
1.
Cell Division and Related Topics
A.
Mitosis
1.
General Considerations
a
Division of the nucleus as part ofnonnal cell division in somatic cells
b.
Mitosis is part of the cell cycle (G 1, S, G2, Cell Division)
c.
Mitosis is accompanied by cytokinesis which is cytoplasmic division
i.
plant cells do not use centrioles but make a middle lamella
ii.
animal cells use centrioles and pinch apart
2.
Phases
a.
Interphase--part of cell cycle--found between divisions, new chromatids are synthesized
b.
Prophase--chromosomes shorten and thicken. each has two chromatids
c.
Metaphase--chromosomes line up in middle of cell
d.
Anaphase--chromatids separate and move apart, each has one chromatid
e.
Telophase--chromosomes lengthen, nuclei are reconstructed
3.
Results
a.
Each daughter cell is identical to the mother cell, diploid cells result
b.
Humans have 22 pairs of autosomes and one pair ofsex chromosomes in each cell
B.
Meiosis
1.
Geneml considemtions
a.
Meiosis is used only in the fonnation of gametes (reproductive cells)
b.
Gametes have only one of each chromosome
b.
Formation of gametes is called 'reduction division' because haploid cells result
2.
Divisions of meiosis
a.
Division I is the separation of chromosome pairs
b.
Interkinesis is between the divisions, its length varies
c.
Division II is the separation of chromatids
3.
Results
a.
Four daughter cells result from each mother cell
b.
The mother cell is diploid, the daughter cells are haploid
c.
The diploid number is restored by the process offertilization
4.
Oogenesis
a.
Oogenesis is production of egg cells
b.
Meiosis produces four nuclei, three are discarded
c.
Result is one haploid egg cell with all of the cytoplasm
5.
Spennatogenesis
a.
Spermatogenesis is production of spenn cells
b.
Meiosis produces four cells which become sperms
c.
Result is four haploid sperm cells; some male, some female
C.
Reproduction
1.
Female reproductive system
a.
Ovaries produce the egg cells by meiosis
b.
After ovulation the egg cell travels through the oviduct
c.
Fertilization results in the restored diploid number of chromosomes
2.
Male reproductive system
a.
Testes produce male and female sperm cells by meiosis
b.
Sperm cells leave the body via the vas deferens and urethra--they enter the vagina
c.
A single spenn cell will fertilize an egg in the oviduct
3.
Fertilization
a.
Fertilization restores the 2n number. The spenn and egg are each n.
b.
After fertilization the embryo begins to develop
2
D.
II.
III.
Embryology
1.
Cleavage stages occur fIrst--in the oviduct
2.
Cleavage results in a morula which is a solid ball of cells
3.
Continued division produces the blastula which is hollow
4.
The blastula folds inward to produce the gastrula--this is about when the embryo implants
a.
The outer layer of the gastrula is the ectoderm
b.
The inner layer of the gastrula is the endoderm
c.
The middle fIlls with cells called the mesoderm
Genetics
A.
DefInitions
1.
allele--contrasting form of a gene--two aneles per diploid cell
2.
genotype--the combination of alleles found in an organism
3.
phenotype--the exterior appearance of the organism without genetic analysis
4.
homozygous--both alleles are the same--can be dominant or recessive
5.
heterozygous--the alleles are different
B.
Simple Mendelian inheritance
1.
A dominant allele is expressed whenever it is present
2.
A recessive allele is only expressed in the absence of a dominant allele
3.
Inheritance of a single trait
a.
P cross of homozygous dominant and homozygous recessive parents
b.
F1 has all heterozygous hybrid offspring
c.
Crossing two F1 organisms gives segregation oJ the alleles
i.
phenotypic ratio is 3: 1 of dominantrecessive
ii.
genotypic frequency of 1 homozygous dominant 2 heterozygous: 1 homozygous recessive
4.
Test cross
a.
Test cross tells genotype of a dominant organism by mating with homozygous recessive
b.
An dominant offspring means organism was homozygous dominant; 1: 1 ratio means heterozygous
5.
Dihybrid inheritance
a.
Two genes assort themselves independently
b.
Resultsina9:3:3:1 ratio
6.
Genetic diseases inherited by simple Mendelian inheritance
a.
Sickle cell anemia--inherited as a recessive gene in people of African descent
b.
Tay-Sachs disease--inherited as a recessive gene in Eastern European Jews
c.
Cystic fibrosis--inherited as a recessive gene among white people
d.
Inherited among any groupo-not limited to anyone group
C.
Sex linkage
1.
General considerations
a.
Females have two X chromosomes, males have only one, the other is Y
b.
Females can carry recessive alleles which are not expressed
c.
Males express recessive sex-linked alleles because they have only one X chromosome
2.
Sex is determined by the male--he contributes the Y chromosome
a.
Girls get on X chromosome from each parent
b.
Boys get the X chromosome from their mother, the father contributes the Y chromosome
Molecular genetics
A.
Deoxyribonucleic acid (DNA)
1.
Sugar is deoxyribose; bases are Adenine, Thymine, Guanine, Cytosine
2.
Found in the chromosomes
3.
Contains the hereditary information that is passed on
4.
Held together by hydrogen bonds
5.
DNA is a self-replicating molecule
3
B.
IV.
Ribonucleic acid (RNA)
1.
Three kinds
a.
Messenger RNA--is the coded message used to make protein
b.
Transfer RNA--brings amino acids to the ribosome to incorporate into a protein
c.
Ribosomal RNA--forms part of the structure of a iibosome
2.
Messenger RNA is made by a process called transcription
3.
The codons of the messenger RNA are decoded and translated to produce a protein molecule
C.
Protein synthesis
1.
DNA is transcribed to make mRNA
2.
mRNA is translated to make protein
3.
The protein is made on the surface of the ribosome
Ecology
A.
General Principles
1.
Ecology is the study of the relationships between organisms and their environment
2.
Physical factors include non-living environmental components such as light, heat and rain
3.
Living factors include living animals and plants in the environment
4.
All living organisms in a given area constitute a community
5.
All organisms of the same species in a given community constitute a population
B.
Pyramid of energy
1.
The source of all energy on the surface of the earth is the sun
2.
The base ofall food chains is a green plant
. 3.
A plant is eaten by a primary consumer which is also aherbivore
4.
A primary consumer is eaten by a secondary consumer
5.
Energy is lost as you travel up the pyramid; poisons are concentrated as you travel up the pyramid
C.
Food chains
1.
A food chain is like a food pyramid
2.
Sequence: Producer, primary consumer, secondary consumer, higher consumer
3.
The last consumer is usually a predator
D.
Food webs
1.
A food web contains several food chains
2.
The food chains in a food web share several common intersections or pathways
E.
Succession
1.
Bare rock is colonized by lichens
2.
Accumulation of material leads to fonnation of deeper and deeper layers of soil
3.
Deeper soil permits growth of larger plants
4.
The ultimate plant in the sequence is the climax vegetation or dominant botanical community
F.
Biomes
1.
Tundra--cold, short growing season, tiny vegetation, no trees
2.
Taiga--too cold for deciduous trees, climax vegetation is mainly conifers
3.
Temperate Deciduous Forest--Moderate climate, sufficient rainfall to support trees
4.
Grassland--Too dry for trees, climax vegetation consists of grasses except near rivers
5.
Desert--Too dry for all except the plants adapted to growing there
6.
Tropical Rain Forest--Abundant Rainfall, growing season is year-long
7.
Marine Biome--contains all marine communities
G.
Material Cycles
1.
Carbon-Hydrogen-Oxygen cycle
a.
Oxygen is the waste product of photosynthesis
b.
Oxygen is used for respiration and combustion to yield water and carbon dioxide
c.
Water and carbon dioxide are used by plants for photosynthesis
4
2.
V.
Nitrogen cycle
a.
Nitrates are removed by plants from the soil
b.
Plants use nitrates to make plant proteins
c.
Animals eat plants and use plant amino acids to make animal proteins
d.
Dead animals and plants are decomposed releasing ammonia
e.
Ammonia is oxidized to provide nitrates
H.
Relationships between organisms
1.
Commensalism
a.
One organism benefits, the other is not harmed
b.
Example: Spanish moss benefits while hanging from trees which are not harmed
2.
Mutualism
a.
Both organisms benefit
b.
Example: Beans and nitrogen-fixing bacteria
3.
Parasitism
a.
The parasite benefits, the host is harmed
b.
Example: Human tapeworm benefits while sickening the host
4.
Predation
a.
One organism attacks another
b.
Example: Lion benefits while antelope is killed
Evolution
A.
The Heterotroph Hypothesis
1.
Primitive conditions on the earth
a.
There was heat, lightning, unabsorbed UV radiation
b.
Primitive atmosphere contained methane, ammonia, hydrogen and water
c.
Experiments have shown that primitive conditions can synthesize biological molecules
2.
Synthesis reactions
a.
Biological molecules were made from primitive gases using electrical discharge
b.
This probably occurred along the coastlines of oceans where high molecular concentrations were
3.
Aggregates of organic molecules
a.
Small organic molecules were synthesized at random
b.
Small molecules combined to produce larger ones
c.
Large molecules began to form aggregates and coascervates
4.
Reproduction of molecular aggregates
a.
Some larger ones began to reproduce
b.
Development of DNA would have helped this
5.
Anaerobic respiration
a.
Anaerobic respiration occurs in the absence of oxygen
b.
Anaerobic respiration still exists in anaerobic bacteria and as a component of aerobic organisms
c.
Molecular oxygen was not found in the atmosphere until photosynthesis evolved
6.
Aerobic respiration
a.
Photosynthetic organisms began to produce molecular oxygen which collected in the atmosphere
b.
Organisms exposed to the atmosphere had to evolve a means to cope with molecular oxygen
B.
Geologic time scale
1.
Oldest rocks are about 4 billion years old
2.
Life evolved at least 3 billion years ago
3.
Most living creatures as we know them are since the last 600 million years
C.
The Fossil record
1.
Fossils are remains of things that were alive or were made by things that were alive
2.
Early Mammals began to develop while dinosaurs were still extant
3.
Dinosaur extinction occurred 65 million years ago after the asteroid hit
4.
Primates developed starting about 70 million years ago; monkeys, about 40 million years ago
5.
Relationships are based on comparative anatomy
5
D.
Fossil record ofhuman ancestors
1.
Proconsul developed during Miocene epoch (25 million years ago)
2.
Ramapithecus developed during Pliocene epoch (12 million years ago)
3.
Early Pleistocene hominids
a.
Australopithecus afarensis lived in East Africa 3.5~'1nil1ion years ago
b.
A. africanus was gracile and evolved from A. afarensis
c.
A. transvaaliensis was robust and died out after 1 million years
d.
IfQmQ.habilis. dates from 1.5 to 2.0 million years ago
4.
Middle Pleistocene men
a.
H. ~ developed in Africa about 1.6 million years ago
b.
H. ~ evolved about 300,000 years ago
5.
Late Pleistocene men
a.
sub-species H. ~ neandertbalis was assimilated about 35,000 years ago
b.
sub-species H. ~~ is today's modemhuman
6.
Evolutionary trends in primates