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bio test 4

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photosynthesis (definition)
the conversion of radiant energy (sunlight) into food. They energy is put into a form that is stable and usable.
change in Gibb's Free Energy is...
positive for photosynthesis
colors of the spectrum?
range of wavelengths for visible light?
red orange yellow green blue indigo and violet (ROY G BIV).
400nm (blue) - 740nm (red)
how much energy do photons have?
they have a certain amount available. The shorter the wavelength, the more energy the photons have.
what does a pigment do?
it absorbs light
What happens when light hits a surface?
it can be absorbed, reflected or transmitted
what is the absorption spectrum?
the wavelengths of color that are being absorbed by the pigments.
What are different types of pigments?
chlorophyll A, chlorophyll B, beta carotene and xanthophyll
When a pigment molecule absorbs light energy, one of three things can happen:
1. an excited e- jumps to a higher level but then falls back releasing the energy as heat
2. the e- jumps to a higher energy level and leaves the molecule and is trapped by an electron acceptor molecule (happens in leaves)3. the e- releases energy it had as heat and light. the light given off is at a longer wavelength and therefore less energetic (fluoresence)
photosynthesis comes in three parts:
1. light dependent reactions (like the Calvin Cycle)
2. Noncyclic photophosphorylation
3. cyclic photophosphorylation
light dependent reactions. what happens? what does it require? where does it occur? example?
The chloroplast takes sunlight and converts it to ATP and NADPH. require pigments. occurs on the thylakoid (in chloroplast).
ex- Calvin Cycle (in stroma)
noncyclic photosphorylation. what happens? (4 things)
*its the e- transport chain that is light dependent.
1. makes ATP and NADPH
2. O2 is formed by photolysis of water
3. photosystems 1 and 2 exist
4. the photosystems are connected by an e- transport chain
cyclic photophosphorylation.
what happens?
1. extra ATP is made
2. only photosystems one functions
3. No NADPH
4. no water is split
5. no oxygen is released
what is RuBISCO?
the most common plant protein and the most common protein on the earth
what are genetics?
the study of hereditary -- the study of nucleus in a cell because that is where DNA is located
what are daughter cells?
cells that are formed by cell division from the mother cell that are genetically identical to each other AND the mother cell
what is cloning?
any cell in the body has the potential to make a new identical organism.
what is septum?
the division between two cells that are about to divide in prokaryotic cells
what is mitosis?
the process in which nuclear division occurs in eukaryotic cells
what is cytokinesis?
the process in which cytoplasmic division occurs
what are the stages of mitosis
interphase
prophase
metaphase
anaphase
telophase
what is interphase?
what are its different phases?
the period between mitotic divisions. It is made of Gap Phase one (G1), Gap Phase two (G2) and DNA synthesis (S).
What is prophase?
when the chromatin material condenses into chromosomes.
chromatin is what % protein and DNA? what are the proteins called?
60% protein -- histones
40% DNA
what do the histones do?
they fold the chromosomes into the nucleus
what is a chromatid?
how many strands of DNA does it have?
one half of a chromosome (chromosomes are double stranded)
it has ONE strand of DNA.
What is the centromere?
condensed region on a chromosome where sister chromatids are attached to each other after replication
What is the kinetochore? What does it do?
the protein structure within the centromere. It helps keep the spindle fibers attached during mitosis
What are the steps of Prophase? (5 STEPS)
1. chromatin condenses into chromosomes (you can see the chromosomes)
2. centriole pairs (microtubule organizing centers) move to opposite poles of the cell. as centrioles separate, spindle fibers are formed
3. manufacture of the spindle apparatus
4. nucleoli disappear
5. nuclear envelope decomposes (end of prophase)
what is the longest phase of mitosis?
prophase
what happens in metaphase?
double stranded chrom. interact with spindle fibers to move them to be aligned on the equatorial plane.
what happens in anaphase?
each double stranded chromosome spearates from one another. (shortest phase in mitosis) Each pole is genetically identical to each other
what does cohesion do?
It holds the chromosomes together
what does separase do?
it separates the chromosomes
what do the kinetochore microtubules do?
they pull the single chromosomes in opposite directions towards the cell poles.
what happens in telophase?
begin: when single chromo. reach pole.
spindle fibers dissapear
nuclear envelope reforms
nucleoli reforms
chromo. --> chromatin fibers
What is animal cell cytokinesis?
when two nuclei divide and a cell plate forms. It grows to the cell membrane and then breaks apart
how does a cell plate form?
vesicles that contain cell wall material will meet in the middle of the cell, fuse and get larget to form the cell plate.
What is the longest phase of interphase? what happens?
G1 (Gap Phase one) is the longest phase of interphase. the cells grow and enlarge. respiration and protein synthesis occur.
What phase of interphase is DNA replicated in?
S (synthesis)
what happens in Gap Phase two of interphase?
(G2) when the cell prepares for the next mitotic division. The organelles (mitochondrion and plastids) replicate themselves
When are cells arrested in interphase?
G0. After G1 the cell goes into G0 if the cells are going to take themselves out of the cell cycle (this is when people stop growing)
what are examples of two types of cells that keep on cycling even though the person has stopped growing?
Stem cells and bone marrow cells (they are responsible for replacing red blood cells).
also melanocytes (stem cells in scalp) and meristems (tip of plant root and leaves)
what are gametes
sex cells - sperm and eggs. in humans they have 23 chromosomes each.
what are haploids
(gametes) only have one set of chromosomes. haploid # of chromo. = n. in humans n=23
what are somatic cells?
they are all other body cells. they are diploids because they have all 46 chromosomes
what happens in the process of fertilization?
what is the result?
occurs when the egg (haploid) unites with a sperm (haploid) to form a diploid.
result: zygote (fert. egg)
what is meiosis?
when does it happen?
*process where a diploid goes to a haploid. the haploid cells formed have new combinations of chromosomes. meiosis immediately follows fertilization.
in meiosis (two things):
1. 2 nuclear divisions occur that give 4 nuclei
2. half the number of chromosomes are in the nuclei as the mother cell
phases of meiosis one:
prophase I
metaphase I
anaphase I
telophase I
phases of meiosis two:
Prophase II
metaphase II
anaphase II
telophase II
what is a homologous pair?
a set of chromosomes that are the same size, shape and have the same genetic information
what happens in metaphase one?
spindle fibers adjust their chromosomes so that they come to the middle of the cell (the metaphase plate)
what happens in anaphase one?
The chromosome pairs separate and go in opposite directions towards the cell's poles. (they are still double stranded)
What is interkinesis?
a short resting phase between meiosis one and meiosis two
what happens in meiosis two??
each nucleus enters as its own and divides into two, so there are 4 nuclei in the end. It is a mitotic division.
what happens in prophase two?
the same thing that happens in prophase one
what happens in metaphase two?
the same thing that happens in metaphase one
what happens in anaphase two?
the centrimeres split and so the chromosomes split. each strand goes in a different direction. the chromosomes are now single stranded
what happens in telophase two? what is the result?
when the nuclear envelope reforms for each of the four nuclei. the result is four gametes
what effects does sexual reproduction have on genetics?
it increases genetic diversity and increases the number of organisms.
How does sexual reproduction increase genetic diversity? (4 ways)
1. various distribution during meiosis one.
2. crossing over
3. random fertilization (random sperm and egg)
4. mutations change DNA
Where does meiosis occur in males? how does the process start?
testes. It starts with a primary spermatocyte. (then two secondary spermatocyte form and there are two spermatids which are the haploids. result: 4 spermatids. occurs during meiosis one and two)
what is the kind of genetics we study?
mendelian genetics
what is spontaneous generation?
an organism sprouts from nothing
what is blending inheritance?
the traits of both parents are blended in the offspring. problem: after a few generations, everyone would look the same
what is a gene?
a particular unit of inheritance. It represents a certain portion of a DNA molecule on a chromosome
what are alleles?
the alternate form of a gene. they occur in pairs. (ex - green allele, yellow allele)
what is Mendel's Law of Segregation?
the paired alleles are seperated during gamete formation (meiosis). There is one allele in each gamete
what is a genotype?
the genetic composition of an organism.
what is the phenotype of an organism?
the physical appearance of an organism.
what is the gene locus?
the location where the gene occurs on the homologous pair of chromosomes
how can you determine the genotype and phenotype of an organism?
to make a punnett square
what is the genotypic ratio?
the ratio of the different combinations of alleles.
what is the phenotypic ratio?
ratio of physical appearance possibiilites
what is a test cross?
when you have a dominant phenotype but nknown genotype crossed with a recessive homozygous genotype
what is photolysis?
the breakdown of water in the presence of light
what are three kinds of spindle fibers?
1. astral microtubules (stabilize the spindle apparatus)
2. pola microtubules (come out from both sets of microtubules and come to the equatorial plane)
3. kinetochore microtubules (grow out from the centriole pairs and attach to the kinetochore)
What did Herwig work with? What did he discover?
worked with sea urchins.
Found nucleus of cell carries DNA
What did Hammerling work with? What did he conclude about his research?
he worked with Alga (Acetabularia)
He concluded that the nucleus controls cellular activities
photosynthesis reaction
C6H12O6 + 6O2 --> 6CO2 + 6H2O
what happens in prophase I? (6 things)
1. four chromo. condense
2. centriole pars seperate
3. nuclear envelope breaks down
4. synapsis (membranes of homo. pairs unite)
5. tetrad forms (chromo wraps around each other)
6. crossing over (arm of one chromo. breaks off and goes to the other)

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