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Biology Final

Ch. 8, 9, 10/11, 12, 13, 15, 16/19
cell cycle
Gap 1, Synthesis, Gap 2, Mitosis/Cytokinesis
made up of G1, S, & G2; cell grows & synthesizes RNA, proteins, & other macromolecules
G1: cell enlarges & makes new proteins
S: cell replicates its DNA
G2: cell prepares to divide
stage in cell cycle where cells don't divide, but perform their "assigned" function
restriction point
point of no return where cell commits to a full round of the cell cycle
phases of mitosis
prophase - nuclear membrane breaks down, chromosomes become visible, spindle begins to form; metaphase - sister chromatids still attached, line up; anaphase - sister chromatids separate & are pulled to opposite ends
splitting of the cytoplasm that divides the cell into two cells after mitosis has occured
plant vs. animal cytokinesis
plant - cell plate forms b/w the dividing cells that becomes the cell wall
animal - cleavage furrow forms in same place that becomes cell membrane
proteins that regulate progression through the cell cycle
tumor suppressor genes
genes that inhibit cell growth
genes that promote cell division & initiate it to start
enzyme that detects mismatches in DNA base pairs
purposes of mitosis
growth, replace dead/damaged cells, repair cells
structure of a chromosome
2 sister chromatids, each made with chromatin & containing genes, attached in the middle by a centromere
properties of DNA
-3D shape (double helix)
-monomer = nucleotides
-nucleotides = phosphate, deoxyribose (sugar), and nitrogen base
-bases = adenine (A), thymine (T), guanine (G), and cytosine (C)
-sides of "ladder" made up of phosphate & deoxyribose
-"rungs" made up of nitrogen bases
shape of double helix described in & by:
1953, by James Watson, Francis Crick, and Maurice Wilkins
DNA polymerase
enzyme that catalyzes the formation of new DNA strands
origin of replication
place where enzymes & proteins involved in DNA synthesis bond to regions on chromosomes
any change in a cell's sequence of DNA
excision repair
removes mutations (DNA repair): enzyme recognizes the mismatch, bonds to DNA, breaks the hydrogen bonds, removes damaged DNA, DNA polymerase fills in correct bases, enzyme fixes the bonds between them
cancer & metastasis
uncontrolled reproduction of cells; benign is noncancerous (tumor), malignant is cancerous;
-metastasis = tumor breaks off & spread throughout the body
3 parts of an RNA nucleotide
nitrogen base (uracil, adenine, guanine, or cytosine), phosphate group, & ribose (sugar)
copying DNA; strand splits apart and complimentary bases are filled in, forming two new strands
the process of making mRNA (temporary copy) from DNA; takes place in the nucleus of the cell
the process of adding amino acids to the growing chain of amino acids in the order specified by the mRNA; mRNA is fed through the ribosome and tRNA adds the amino acids according to what the mRNA says; takes place inside the ribosome
codons/how many/how many amino acids
a codon is an mRNA triplet, there are 64 but only 20 amino acids; start codon is AUG and stop codons are UAA, UAG, UGA
tRNA triplet, bonds to complimetary codon on mRNA
RNA processing
primary transcripts of mRNA are processed - mG (5') cap is added to starting end, poly-A tail is added to opposite end, introns (noncoding stuff) is cut out (aka splicing) and exons (code for proteins) are linked back together by ligase
A site
the site where the charged tRNA sits while it adds its nucleotide to the sequence
P site
the site where the second tRNA bonds to the codon that's "waiting"; the tRNA is "waiting" to reach the A site & add its amino acid to the chain
the ribosome attaches at a specific site o the mRNA (start codon AUG)
peptide bonds join each amino acid with the next on the chain
when stop codon reaches the A site, release factor binds to the stop codon in the A site & translation stops
frame shift mutation
sequence "shifts" b/c one nucleotide off, changes into different amino acids and the start/stop codons are at different places or gone altogether
structure of a virus
DNA/RNA coated in protein; have some characteristics of life, but not all
virus that infects bacteria
lyctic vs lysogenic
--lyctic injects its genetic material into the cell, the genetic material enters the cell's DNA, the cell copies the DNA to RNA and some of it gets made into proteins, cell assembles virus, cell explodes, more viruses are relased
--lysogenic = viral DNA makes a circle & inserts itself into the host DNA, the cell's daughters have that viral DNA, & eventualy the virus becomes active & follows lyctic cycle
fertilization (animal)
union of 2 cells (egg & sperm)
sex cells (egg & sperm)
fertilized egg
widdul baby organism! aww :)
egg's metabolism is turned on after fertilization; it then blocks fertilization by a second sperm & the zygote cytoplasm is rearranged by movements in the cytoskeleton (causes differences among cells when they divide)
some genes in a cell are turned off & the rest are expressed, which guides the development of the embryo & forms specific cell types
beginning of the shape / development of the structure of the organism
animal embryo after cleavage stage; hollow fluid-filled ball of cells (simplest embryos are solid)
formed when the blastula folds in on itself; layered, cup-shape embryonic ball; inner cell mass becomes embryo, embryonic stem cells become placenta
primary germ layers
ectoderm: nails, skin, hair, nervous system
mesodern: heart, blood, bones, muscle, sex organs, notochord (backbone)
endoderm: digestive system lining, lungs, bladder, pancreas
cell specializaton/division of labor
cell specializes to perform a certain function in the body (determined by proteins)
bilateral - fish
radial - sea anenome
neural tube
becomes spine, can cause sever defects if it doesn't close properly
-egg --> larva --> adult
-complete also changes lifestyle (frogs)
-incomplete (most beetles)
division of the body into a number of similar sections
homeotic genes
genes that say where to turn on gene & how long to turn it on for (where parts belong)
homeotic genes in mammals; all are contained in this, & they turn on the transcription of other genes
human blastula
amnion = surrounds embryo
chorion = encloses all other membranes
villi = fingerlike projections into the lining of the uterus
placenta = chorionic villi + uterine lining; exchanges wastes, nutrients, & oxygen
tissue that surrounds the plant embryo and transfers nutrients to it from the mother plant
seeds leaves that carry on photosynthesis until the true leaves are developed
apical meristems
zones in the root & tip of undifferentiated cells (like stem cells, but in plants)
primary vs. secondary growth
primary = growth from the merisems present in embryo
secondary = growth in some older plants where the stem & roots grow horizontally in diameter
circle of DNA present in bacteria
recombinant DNA
DNA that was cut from a human gene using restrcition enzymes & then inserted in a bacterial plasmid
genetic engineering in medicine & agriculturally
medicine = creates better, more effective medicines & vaccines
agriculture = creates better crops that are resistant to pesticides & disease
asexual reproduction
a single parent produces offspring that are genetically identical to it; binary fission, budding, fragmentating, mitosis, cloning
one set of chromosomes
double set of chromosomes
diploid # for an organism
haploid # for an organism
daughter cells
cells resulting from mitosis (2, diploid, identical) or meiosis (4, haploid, different)
somatic cells
body cells; are diploid, reproduce by mitosis
sex cells; are haploid (male - sperm, female - eggs), reproduce by meiosis
sex chromosomes
determines the sex of offspring; X = female & Y = male, so XX = female & XY = male
--Prophase I - homologous chromosmes pair up & cross over
--Metaphase I - tetrads (pairs of homologous chromosomes) line up
--Anaphase I - pairs of homologous chromosomes split up
--Telophase I/cytokinesis: 2 haploid cells form, chromosomes still are w/ sister chromatids
--Prophase II - 2 cells have separated
--Metaphase II - sister chromatids line up
--Anaphase II - sister chromatids separate
--Telophase II & cytokinesis - haploid daughter cells form
meiosis in males vs. females
male - proceeds as normal
female - forms one "big" egg with all of the cytoplasm and two polar bodies that are small cells containing chromosomes that eventually disintigrate
3 ways genetic diversity is generated in meiosis
-crossing over = homologous chromosomes exchange corresponding pieces of DNA
-distributes a random mixture of parent's maternal & paternal DNA to each gamete
-independent assortment =alleles for one characteristic divide up randomly b/w gametes independently of alleles for another characteristic
conjugation (in bacteria)
a tube of cytoplasm connects 2 bacteria and they are temporarily connected to pass DNA through the tube & promote variation
meiosis vs mitosis
in meiosis:
-cell divide twice, but chromosomes aren't duplicated after 1st division
-distributes a random mixture of maternal and paternal DNA to the gametes
-involves 2 nuclear divisions that produce 4 haploid cells
parts of a seed
seed coat - encloses endosperm & embryo
endosperm - gives seed nutrients from the mother plant
embryo - baby plant
parts of a seedling (germinated seed)
-primary root (main root); emerges out of the seed first
-secondary root (little roots that branch out)
-stem (called coleoptile in monocots)
sprouting of the seed - needs favorable temperature, water, & O2; the seed begins to form into an adult plant
period of time where the seed dries out and stops growing; cellular respiration slows to an extremely low rate & the seed can remain alive for years
the transfer of pollen from anther to carpel; the pollen travels to the stigma
fertilization (plants)
1 pollen grain meets with the ova, and one pollen gain meets with the two polar nuclei (forming the endosperm)
seeds are spread & carried to different locations by humans, birds/animals, insects, wind, water, etc.
**monocot vs. dicot**
parts of a flower
-female: pistil, ovule, style
-male: anther, filament, stamen
process of fertilization in plants
pollen grains land on style & form a pollen tube through the pistil and into the ovary
angiosperm vs. gymnosperm
angiosperm - flowering plant, seeds protected in flower
gymnosperm - "naked seed", seeds protected in cone (like a pine tree)
internal fertilization
male releases sperm into femal reproductive organ
external fertilization
gametes released into the environment (very inefficient)
menstrual cycle
1) estrogen & progesterone are at low levels, hypothalamus secretes GnRH
2) pituitary releases FSH & LH that act on ovary
3) FSH causes egg to start maturing inside follicle
4) LH & FSH stimulate the release of more E
5) E signals uterus lining to thicken
6) sudden increase in LH causes egg to release
7) follicle becomes corpus luteum & continues releasing E & P that further build up lining of uterus
8) FSH & LH slow down, P & E slow down
9) uterus lining declines
follicle & corpus luteum
follicle = fluid-filled sac where egg matures
corpus luteum = ruptured follicle that releases estrogen & progesterone
human pregnancy hormone released by placenta; signals the corpus luteum to continue releasing progesterone & estrogen
adrogens & testosterone
androgens - group of male hormones
testosterone - major androgen secreted by testes, controls development of 2ndary sex characteristics
Gergor Mendel
-monk & gardener
-concentrated on 7 traits that didn't "blend" when he studied pea plants
Mendel's principles
-segregation: separation of factors into the gametes; each gamete has one allele for a gene, not 2
-independent assortment: alleles for one characteristic divide into gametes independently of the alleles for another
monohybrid & dihybrid crosses
monohybrid - cross where parents differ in one trait
dihybrid - cross where parents differ in two traits
the chance that an event will occur; # of successes over # of possible outcomes
genetic makeup of an organism
expression of the genotype; appearance/function; observed trait
allele that masks the presence of another allele of the same gene in a heterozygous organism
a trait whose expression is masked in a heterzygous organism
one of the 2 (sometimes more) possible forms of a gene
having 2 identical alleles for a given trait
having 2 different alleles for a given trait
P generation
parent generation; parents of the "original" generation in a cross
F1 & F2 generations
1st fillial - 1st generation of hybrid offspring
2nd fillial - 2nd generation of hybrid offspring from the interbreeding of the F1 generation
both alleles are expressed in heterozygotes (ex: calico cats)
incomplete dominance
the phenotype of a heterozygous organism is intermediate between the parents (ex: pink snapdragon)
multiple alleles
more than 2 alleles for a gene (ex: blood type)
sex-linked trait
carried on the x-chromosome, more often found in males because whatever allele on the the x-chromosome they have is the one that's expressed
monosomy & trisomy
monosomy = only 1 chromosome
trisomy = 3 chromosomes
Klinefelter's syndrome
XXY - tall, sexually underdeveloped males, slight mental disability
Down syndrome
extra 21st chromosome - short, severe mental disability, heart defects
Turner's syndrome
X0 - short, sexually underdeveloped, infertile females
translocation (chromosome mutation)
parts of the chromosomes break off and exchange positions
deletion (chromosome mutation)
large region of the chromosome is deleted
inversion (chromosome mutation)
part of the chromosome is "cut", flipped, and put back into place
addition (chromosome mutation)
part of a chromosome is added to another
Human Genome Project
-study genomes of humans & other organisms
-determine the sequence of about 3 billion base pairs of DNA on 24 different chromosomes
-study how genes function
functional genomics
the study of DNA sequence information to help explain cell functions
computer analysis of DNA segments using probes, can be used to examine the expression of genes
recombinant DNA technology
restriction enzymes cut out a gene from human DNA, cut a bacterial plasmid open, insert the recombinant DNA into the plasmid, and then the plasmidproduces the DNA (ie insulin)
polymerase chain reaction - makes many copies of a small sample of DNA
single nucleotide polymorphism - genetic variations in which alleles differ by only one or a few scattered nucleotides
RFLP analysis
restriction fragment length polymorphism analysis - compares lengths of fragments of DNA after restriction enzymes cut them apart, then are separated by size through electrophoresis
gel electrophoresis
DNA is inserted into the wells of a gel, the gel is placed inside a buffer solution (conducts electricity), DNA moves through holes in gel from negative to positive, short fragments move farther & longer don't go as far
a change in the gene pool of a population over generations
evolutionary change on a large scale, including speciation, evolutionary trends, adaptive radiation, & mass extinction
population genetics
the sudy of the genetic of groups of interbreeding individuals
gene pool
all of the genes of a local population of organisms
Hardy-Weinberg model & assumptions
-model of gene pools
-p = dominant, q = recessive: p² + 2pq + q² = 1,
p + q =1
-assumes that: organism is diploid, generations don't overlap, large population with little mutation/ migration, no natural selection, sexual reproduction, & gametes unite at random
modern definiation of evolution
change in population over time
the continuous adaptation of different species to each other
malaria & sickel-cell alleles
both high in the same areas b/c the sickle-cell allele protects against malaria
difference b/w theory and a law
theory is explanation supported by evidence that can be revised with new evidence, but law just states something; theory holds more weight b/c it has explanatory power
use/disuse, organisms aquire adaptations in their lifetime & then pass them on to offspring
natural selection, said that organisms already ahd their genes & that the organisms most adapted to their environment & thus able to leave the most offspring were the "fittest"
differences in amino acids chains of humans & gorillas
caused by a mutation
the study of fossils
fossil/ "gaps" in fossil record
the fossilized remains of ancient organisms; impint or cast of the bones; "gaps" are there because very few organisms actually became fossils, & so some species do not have any existing fossils at all
Malthus, Lyell, & Wallace
Malthus - overpopulation, struggle for existance; Darwin wondered if this could apply to humans
Lyell - uniformitarianism
Wallace - same ideas as Darwin, but recognized that Darwin thought of them first
artificial vs. natural selection
artificial selection is controlled by the breeder, natural selection is controlled by nature
homolougous & analogous structures
homologous structures = have same structure in different species (human arm & bat wing)
analogous structures = similar function b/c they share the same purpose/environment
genetics provides evidence for evolution b/c...
-similar amino acid sequences
-DNA / molecular evidence
-similarities in development
isolation mechanisms
-behavioral: premating rituals differ
-geographic: separated by distance or geographic barrier
-seasonal: different times
-genetic: infertile offspring/incompatible
types of selection
-disruptive selection: extremes selected for
-stabilizing selection: middle selected for, curve becomes narrow
-directional selection: one side of the curve is selected for, curve shifts position
graudalism vs. puncutated equilibrium
gradualism: gradual changes over time
punctuated equilibrium: rapid periods of change followed by long periods of stasis