Topics 3-4 Flashcards
Catabolic Pathway and types
molecules are broken down and their energy is released. catabolic pathways yield energy by oxidizing organic fuels
Types
Fermentation
Cellular Respiration
What type of reaction is cellular respiration? what is it used for?
exergonic, release energy from glucose to phosphorylate ADP to ATP
What can be broken down for energy in cellular respiration, and what us mainly used?
Carbs, fats and proteins can be used but glucose is the primary nutrient for it
What is the cellular respiration reaction?
C6H12O6+6O2▶️6CO2+6H2O
Exergonic
NAD+
A coenzyme that serves as an electron carrier in cellular respiration, it stabilizes to form NADH when it receives 2 electrons
Glycolysis
Location: Cytosol
What happens: Glucose(6 carbon) is broken down into 2 pyruvate molecules(2, 3 carbon sugars) and 2 water molecules
Phases:
- Energy investment, 2 ATP used, 2ADP+2P yielded. Glucose is destabilized and made more reactive
- Energy payoff phase: 4ADP+4P form 4ATP. 2NAD+, 4 electrons, and 4H+ yield 2 NADH+2H20
Net: +2ATP(4 gained 2 used)
2 NADH+2H+ from energy payoff phase
What are the 2 NADH from glycolysis used for
They are utilized in the electron transport system
What happens between glycolysis and he citric acid cycle?
Pyruvate is oxidized to Acetyl CoA. transport protein moves pyruvate from the cytosol to the mitochondrial matrix, where an enzyme complex removes CO2, strips away electrons to convert NAD+ to NADH and adds coenzyme A to form acetyl CoA(2 per glucose).
Citric Acid cycle
Location: Mitochondrial Matrix
Purpose: The task of breaking down glucose is completed with CO2 released as waste
What happens: One input of Acetyl CoA=1 turn of the cycle, meaning 2 turns completely oxidizes glucose
Result from 1 turn: 2CO2, 3NADH, 1FADH2, 1 ATP
*each glucose yields twice these
What holds the energy in cellular respiration?
The electrons within the electron carriers
Oxidative Phosphoration
Purpose: Chemiosmosis couples electron transport to ATP synthesis, includes ETC
Location: Inner mitochondrial membrane
What happens: the ETC takes H+ from NADH and FADH2 and pumps it from the mitochondrial matrix to the intermembrane space to create a gradient, which powers chemiosmosis. The H+ go to the end of the ETC where a final electron acceptor, typically O2, bonds with them
Chemiosmosis
ATP synthesis powered by the flow of H+ across the gradient created by the ETC. It is an energy coupling mechanism
ATP Synthase
A transmembrane protein in the mitochondrial membrane containing a channel where H ions flow back down their gradient
Proton motive force
The gradient of hydrogen ions that phosphorylates ADP to ATP
How much ATP is yielded from Cellular Respiration? Oxidative phosphorylation?
Cellular Respiration: 30-32
Oxidative Phosphorylation: 26-28
Fermentation
An expansion of glycolysis where ATP is generated by substrate level phosphorylation, with NAD+ being the electron acceptor instead of Oxygen
Alcohol and lactic acid fermentation
Alcohol: pyruvate is converted to ethanol, releasing CO2 and oxidizing NADH in the process to create more NAD+
Lactic Acid: Pyruvate is reduced by NADH while forming NAD+ and lactate is the waste product
Facultative and obligate anaerobes
Facultative: Can make ATP by aerobic respiration if oxygen is present but can switch to fermentation under anaerobic conditions
Obligate: Can not survive in the presence of oxygen
Chloroplasts
Location: Mesophyll tissue found in the interior of the leaf
Sites of photosynthesis
Stroma
A dense, fluid filled area. Enclosed by 2 membranes, made up of thylakoids. Sight of Calvin cycle
Thylakoids/thylakoid space
Vast network of interconnected sacs inside the stroma, segregating the stroma from the thylakoid space. Contains chlorophyll. Sight of light reactions
Chlorophyll
Location: thylakoid membranes
Light absorbing pigment that drives photosynthesis and gives plants green color
Photosynthesis reaction
6CO2+6H20+Light Energy▶️C6H12O6+6O2
Endergonic
Light reactions
Location: Thylakoid membranes
Products: NADPH, ATP and Oxygen gained, O2 released
What happens: Light is absorbed by chlorophyll and drives transfer of electrons from splitting water to NADP+, forming NADPH. ATP is generated using chemiosmosis to power photophosphorylation, when the electrons go down the ETC between photosystems. Electrons are providing from the splitting of water, where they then enter photosystem II. O2 is released into the atmosphere from here. After PII, electrons are transmitted to NADP+, forming NADPH for the calvin cycle
Calvin cycle
Location: Stroma
3 CO2 molecules are used to make 1 G3P, used one at a time. 3 of then are attached 5 carbon molecules of Rubisco Biphosphate(RuBP). The reactions that fix carbon are catalyzed by the enzyme rubisco.
Phases:
1. Carbon fixation: 6 ATP and 6 NADPH used.
- Output: G3P released
- Regeneration of RuBP: 3ATP used
Pigments
Absorb specific wavelengths of light
Photosystems
Location: Thylakoid membrane of chloroplasts
Groups of pigment molecules that absorb photons
Parts: Light harvesting complex and reaction center
Light harvesting complex
Made up of many chlorophyll and carotenoid molecules, allowing light to gather effectively. When the chlorophyll absorbs photons, one of the molecule’s electrons is raised to a higher orbital of potential energy, putting the chlorophyll in an excited state.
Reaction center
Consists of two chlorophyll a molecules, which donate the electrons(oxidizing) to the second primary electron acceptor(solar powered). This is the first step of the light reactions
linear(cyclic) electron flow
the key to light reactions, the flow of electrons through the photosystems in the thylakoid membranes
Where does chemiosmosis take place during photosynthesis?
thylakoid space
In what instances is H+ moved from the stroma to the thlykoid space?
- Splitting of water
- Pumping of electrons across the membrane by the cytochrome complex
- NADP+ is reduced to NADPH take H+ from stroma
C4 plants
CO2 is added to PEO to form a 4 carbon compound called oxaloacetate, which does not combine with O2 instead of CO2 to cause photorespiration
CAM plants.
Close stomata during the day to prevent water loss, CO2 is stored in organic acids and are released in the morning when the stomata close
Compare and contrast the differents types of photosynthesis
Similar: In both C4 and CAM-CO2 is transformed into an organic intermediate before it enters the calvin cycle. All processes use calvin cycle
Different: Different methods are used to get to the calvin cycle
Homologous chromosomes
both chromosomes of each pair carry genes that control the same inherited characteristics
Interphase
- Chromosomes duplicate, doubling amount of DNA in the cell
* Centromere divides
Prophase 1
- Chromosomes condense, resulting in 2 sister chromatids attached at their centromeres
- Synapsis/Crossing over
- Centrioles move away from each other
- Nuclear envelope disintegrates
- Spindles microtubules attach to kinetochures and metaphase begins
Synapsis
joining of homologous chromosomes along their length
Result of meiosis 1
2 haploid daughter cells
Prophase 2
- Spindle forms
* Sister chromatids move towards metaphase plate
What occurs in meiosis and not mitosis?
- Crossing over/synapsis
- homologous chromosomes are positioned along the metaphase plate instead of individual replicated chromosomes
- In anaphase 1, duplicated sister chromatids stay together, while they separate in mitosis
Sources of genetic variation
- Crossing over
- Independent Assortment of chromosomes: In metaphase 1, homologous chromosomes line up on the metaphase plate, paired up in any combination with any pairs facing either pole. This gives a 50% chance of getting a pair from each parent
- Random fertilization: Each egg and sperm are different because of independent assortment and crossing over, making each egg and sperm combo unique
codominance
two alleles are dominant and effect the phenotype in two separate but equal ways(blood types)
Pleiotropy
property of one gene to have multiple phenotypic effects
Epistasis
a gene at one loci effects a gene at another loci
Polygenic inheritence
two or more genes have an additive effect on a single character in the phenotype
