bio Flashcards
Photosynthesis facts
Chloroplasts in eukaryotes consumes CO2 + H2O produces sugar + O2 Anabolic Reduction of CO2 to sugar: C02+H20-->c6H12O6 +O2 Requires light + photopigments Photoautotrophs only Overall consumption of ATP Photolysis Calvin Cycle NADPH
Respiration Facts
Mitochondria in eukaryotes consumes CHO + O2 Produces ATP + CO2 catabolic Oxidation of sugar to CO2 C6H12O6 +O2-->CO2+H2O Requires carbohydrates All living organisms Overall production of ATP Glycolysis & citric acid cycle Anaerobic & Aerobic NADH + FADH2
What is another process by which energy can be acquired ?
Chemosynthesis
What is Chemosynthesis
Its the synthesis of organic compounds by bacteria or other living organisms using energy derived from reactions involving inorganic chemicals, typically in the absent of sunlight
Example of a Light independent Reaction
Calvin Benson Cycle: It occurs in the stroma, has three phases (Carbon fixation, Reduction & Regeneration of CO2 acceptor)
Describe the carbon cycle in the Calvin benson cycle
An input of CO2 is reduced to a 3-carbon sugar called G3P (Glyceraldehyde-3-phosphate) With by-products of ADP & NADP+ +P.
Carbon fixation in the calvin cycle
3 molecules enter the cycle one at a time & attaches to a 5-carbon sugar, RUBP (ribulose diphosphate, ctalyzed by rubisco. The 6- carbon sugar is short lived as it is very unstable & splits into 2 three carbon sugars
Distinguish between C3 & C4 plants
C3 plants: the bundle sheath cells do not contain chloroplasts.
C4 plants: the bundle sheath cells contain chloroplasts.
C3: the carbon dioxide fixation takes place only at one place.
C4: the carbon dioxide fiction takes place twice
Where does the carbon dioxide fixation occur in C4 plants?
One occurs in the mesophyll cells & the second takes place in bundle sheath cells
Describe Glycolysis in cell respiration
Depending on whether there is oxygen present or not, will determine whether pyruvate will undergo aerobic/anaerobic respiration or fermentation.
Glucose is broken down into 2 pyruvate molecules
input of 2 ATP molecule yields 4 ATP(net 2 ATP) & 2 NADH
Anaerobic respiration & fermentation
O2 Absent (doesn't need it) Happens in the cytoplasm 2 ATP for every glucose molecule Lactic acid is produced Frees up NAD+ Nitrogen & sulphur are final electron acceptors
Aerobic respiration
KREBS CYCLE/CITRIC ACID CYCLE O2 Present (needs it) 38 Molecules of ATP CO2 & water produced Happens in cytoplasm & mitochondria occurs in plant & animal cells
Krebs cycle/citric acid cycle
Input of 2 pyruvate molecules to yield 2 ATP molecules, 8 NADH & 2 FADH2
CO2 is waste electrons from NADH & FADH2 drive electron transport chain
what is the Electron Transport chain
electron from kerbs cycle provide energy to proton pumps in inner membrane of mitochondria
proton pumps move H+ ions from mitochondrial matrix to inter membrane space creating an H+ gradient
H+ moves through diffusion ATP Synthase
ATP synthase converts ADP +Pi to ATP through process of chemiosmosis to yield about 28 ATP
How much ATP does the entire process of cell respiration produce
32 ATP
2 for glycolysis
2 from Krebs cycle
28 from Electron transport chain
what are Chromosomes
they are the vehicle by which hereditary information is physically transmitted from one generation to the next
each chromes carries a linear sequences of genes, the units of hereditary info that given the development phenotype
What are diploid organisms
they have two chromosome sets, one from each parent,
one gene for a given trait resides on chromosomes derived from one parent & its allelic partner resides on the homologous chromosome derived from the other parent.
What happens to homologous chromosomes during meiosis
Each member becomes separated from the the other, then is assorted into gametes. Whole chromosomes are assorted independently of one another there can be different combination of chromosomes from both parents in different gametes.
What happens to a homologous pair during Meiosis I
homologous chromosomes exchange parts as a result of crossing over.
what is a a structural change a chromosome can go through (mutations)
deletions
duplications
inversions
translocation
Describe Structure & function of a chromosome
A chromosome is a DNA molecule with a threadlike structure of nucleic acids & protein found in the nucleus of most living cells
Define Karyotype
an ordered display of chromosome of a diploid cell.
Human somatic cells have 23 pairs
22 homologous pairs (autosomal chromosome)
the 23rd pair is the sex chromosome
sex chromosome of male is not homologous (XY)
What is a mutation
chromosome mutation that results in individuals with more than one haploid set of chromosomes in a cell is termed polyploid
what is deletion
the breakage of a chromosome in which the genetic material becomes lost during cell division. the genetic material can break off from anywhere on the chromosome.
when does duplication occur
produced when extra copies of genes are generated on a chromosome
what happens in inversion
the broken chromosome segment is reversed & inserted back into the chromosome.
pericentric inversion: inversion encompasses the centromere of the chromosome
paracentric inversion: if it involves the long or short arm of the chromes & does not include centromere
Translocation
joining of a fragmented chromosome to a non homologous chromosome
Trisomy
is a chromosomal disorder characterized by an assertional chromosome so the person will gave 47 instead of 46. (Down syndrome)
Polyploidy
is a heritable condition of possessing more than two complete sets of chromosomes. common among plants & certain group of fish
DNA replication requires..
unwinding
construction
coupling
proofreading enzymes
Describe the process of mitosis
the chromosomes condense, divide, & are separated into two sets, one for each daughter cell
Haploid cell
Have only one copy of each chromosome representing the basic genetic complement. Also called gametes (n)
diploid cells
Have two copies of each chromosome (2n)
Describe the process of meiosis
a diploid cell is converted into several haploid cells, 2 successive cell divisions take place.
Explain how DNA replication is bidirectional
it proceeds in 2 directions at the same time from one or more origins
only one origin exists in prokaryotic DNA
thousands exist in eukaryotic DNA
What is the replication fork
is the limited v-shaped region where the enzymes unzip the parent molecule & simultaneously assemble new DNA on the exposed regions of the parent strand
What is DNA polymerase
functions to bind complementary base pairs to parent strand to produce 2 new daughter strands
Describe cytokinesis in animal cells
cells develop a cleavage furrow & contractile ring
Describe cytokinesis in plant cells
golgi vesicles creare a cell plate
define genes
distinct units of heredity, they are the physical basis for all traits of an individual
define locus
a particular location on the chromosome, each gene has its own locus
define allele
the alternative form where a gene for any given trait may occur
define gene pair
two alleles at a given locus constitute a gene pair
homozygote
when the two alleles of a gene pair are identical (AA, aa)
heterozygote
when the two alleles of a gene are NOT identical (Aa)
distinguish between dominant & receive trait
dominant trait is one that is observable in heterozygotes
recessive trait is one that is observable only in homozygous
distinguish between genotype & phenotype
genotype refers to an individuals genetic makeup, may mean a single gene pair or the sum total of genes in an individual
phenotype refers to an individuals observable traits (structure, physiology, behaviour)
describe a punnett square
visual representation used to determine a hypothetical offspring phenotype & genotype ratio
describe a codominant allele
the two alleles both affect the phenotype in separate & distinguishable ways where the phenotypes of both alleles are expressed & visible
2 Main principles of Mendels inheritance
Principle of Segregation
Principle of Independent assortment
Principle of Segregation
segregation of alleles occurring in anaphase I leaves each chromosome with one allele from a parent to the opposite side of the centrosomes
Principle of Independent assortment
describes the behaviour of the homologous pairs aligning at the metaphase plate with no association relative to other pairs
what is rNA
Ribosomal nucleic acid- functions to transcribe genetic material from DNA
Describe Transcription
occurs in the nucleus, begins where RNA polymerase binds itself to the promoter (codon that begins initiation) & unwinds the DNA strands
