Exam 3 Flashcards
Photosynthesis
the process that converts solar energy into chemical energy within a chloroplast
6CO2+12H2O+light energy ——->C6H12O6+6O2+6H2O
Light dependant reactions
Happened in the membrane of the thyalkoid, protons are pumped from the stroma into the thylakoid lumen
reactants: photons and water
products NADPH and ATP
light absorbed into PSII, exciting an electron and passed down the ETC, providing energy for the proton from water (which comes from the oxidation of water) to be pumped across the membrane to create a gradient. light is again absorbed in PSI and electrons are excited again and transferred down the chain. @ the very end of the chain electrons are passed to NADP+ to make NADPH. ATP synthase then pumped the protons back over the membrane creating ATP
Calvin Cycle (light independent reactions)
In the stroma
1 CARBON FIXATION: 3 molecules of Carbon dioxide to start, carbon has been removed from the atmosphere and fixed into an organic molecule, rubisco, then becomes 6 3-PGA
2 REDUCTION of 3-PHA to G3P: ATP is used to convert 3 PGA into 1, 3-bisphosphoglycerate
NADPH electrons reduce it to 6 glyceraldehyde-3-phosphate (G3P)
3CO2»» 6 G3P
Only 1 G3P molecules are used for carbohydrates
the other 5 G3P molecules must be used for the regeneration of RuBP
3 REGENERATION of RUBp: 5 G3P are converted into 3 molecules RuBP using ATP
Genome
All the DNA in a cell
Consists of a single DNA molecule or a number of DNA molecules
Chromosome
Packages of genetic information
**humans have pairs 23 pairs or 46 chromosomes
Autosomes
a type of gamete (doesn’t include sex chromosomes s the xx or xy)
22 pairs in humans
Sex chromosome
1 pair (xx or xy)
Haploid
single chromosomes
represented by n (only 23 chromosomes)
gametes
Meiosis
Diploid
two chromosomes
represented by 2n
somatic cells (all different cells in the body)
created by mitosis
Somatic cells
(Non representative cells) have two sets of chromosomes
Gametes
(Reproductive cells sperm and egg cells)
Have only 23 chromosomes (half as many as somatic cells because they combine with the egg and the sperm to produce a total of 46 chromosomes)
Homologous chromosomes
Look the same, control the same traits, may code for different forms of each trait, made of sister chromosomes joined at centromere
G1 phase (interphase)
Cell growth occurs
Signaling molecules can cause cell to accumulate molecular changes during g1 that promote progression through the cell cycle
If the cell passes the check pt (restriction pt) then it continues to S phase. If not then it goes into G0 pahse
G0 phase
phase in which cells go when they don’t pass the checkpoints in mitosis
In this phase, the cells are neither dividing or preparing to divide
S phase
Chromosomes replicate
After replication 2 copies stay joined together and are called sister chromatids
G2 phase
Cell synthesizes proteins needed during mitosis and cytokinesis
Organelles replicate
46 pairs of chromatids/92 chromatids total
Checkpoints in mitosis
G1 checkpoint: restriction point, checking to see if the cellis ready to divide, if not goes into G0 phase
G2 checkpoint: checking DNA
M checkpoint: check chromosomal alignment
Mitosis phase order
Interphase (G1, S, G2)
Mitosis (prophase, prometaphase, metaphase, anaphase, telophase)
Cytokinesis
Prophase
Nuclear membrane dissociates into smallvesciles chromatids condense into highly compacted structures (visible by light)
Mitotic spindles form
Prometaphase
Nuclear envelope complete fragments
Mitotic soindle fully formed
Cpindle fibers interact, 2 kinetochores on each pair of sister chromatids are attached to kinetichore microtubules from opposite poles
Metaphase
Pairs of sister chromatids are aligned along a plane halfway brown the poles (metaphase plate)
Organized into a single row
Anaphase
Connections broken brown sister chromatids
Each individual chromatid slinked to one pole by the minted horse microtubules
Microtubules shorten pulling chromosomes toward pole where they are attached
Telophase/cytokinesis
Chromosomes have reached respective poles and deco dense
Nuclear membranes now reform to produce two separate nuclei
Cytokinesis
Process called cleavage, first shown by the sign of a cleavage furrow and cell plate in plant cells
Mitotic spindle
Composed of microtubules, Centriols ones which duplicate at beginning of mitosis organize chromosomes
Kinetochore
Center of chromosome associated with centrimeres microtubules attach to kinetochore
Heredity
The transmission of traits from one generation to the next
Through gametes
Meiosis
Nuclear division that precedes the formation of gametes resulting in a halving of chromosomes forming a haploid cell
I 2 haploid cells
II 4 haploid cells
Synapasis
Joining of DNA from one non sister chromatids to the corresponding segment of another allowing crossing over to occur
Happens in prophase I
Synaptonmal complex
A protein complex connecting homologous chromosomes
Crossing over
Physical exchange brown chromosome pieces of the crossing bivalent REGULATED
Chiasma
Arms of the chromosomes separated but remain adhered at the cross over line
futher def: the point of contact or the physical link between two chromosomes in a tetrad as they are crossing over in porphase I
Genetics
Branch of biology that deals with heredity and variation of organisms
Gene
Unit of heredity
A section of dna sequence encoding a single protein
Genome
The entire set of genes in an organism
Alleles
2 genes that occupy the same position on a homologous chromosome and that cover the same trait
onefrom the mother and one from the father
ex. RR, Rr, rr
Locus
A fixed location on a strand of dna where a gene or one of its alleles is located
Dominant
The allele of a gene that makes or suppresses the expression of an alternate gene
Recessive
An allele that is masked by a dominant allele only appearing when in the heterozygous condition
Monohybrid cross
Genetic cross involving a single pair of genes
Law of independent assortment
the inheritance of one pair of genes is independent of the inheritance of another pair
Law of segregation
every individual possesses two alleles and only one allele is passed on the to offspring
Law of dominance and uniformity
One allele masks another; one allele was dominant over the other in the F2 generation
Autosomal mutation
Caused by alleles on autosomes
Chromosomes instead of sex chromosomes
Sex linked mutation
Caused by mutation in X chromosome (most of the time)
Sex linked gene
Gene located on either sex chromosome
X linked genes
Genes found on the x but not on the y
Most sex linked traits are on the x
I order to be expressed a female needs two copies of the allele and a male needs only one copy of the allele
