Chapter 2 and 3 Flashcards
Chemical Components of Living organisms include:
- organic- carbon compounds
- reactions take place in aqueous solutions (70%) water
- reactions take place in a very narrow temp range
- complex
- dominated by large polymers (proteins, DNA, RNA, sugars, lipids)
Important molecules in cells
Methyl- CH3 Hydroxly- OH (alcohols) Carboxly- COOH Carbonyl- C+O Phosphate- PO3^2- (in atp) Amino- NH2
Condensation Reactions
- generates water and forms multimers- anabolic- building
(occurs between two –OH groups)- (Figure 2-17) ex. Glucose + Fructose = sucrose + water
Hydrolosis Reactions
water is consumed and smaller molecules are formed- catabolic- breakdown. Ex. Sucrose + water = glucose + fructose
Fatty acids in cell membranes are _____
amphipathic since it has a hydrocarbon chain which is hydrophobic and a carboxyl group which is hydrophilic
saturated fatty acid with no double bonds in tail
Unsaturated fat= contain one or more double bonds in tail which creates kinks and can’t pack closely
- make up phosholipids ( fatty acids glycerol and phosphate)
Facts about amino acids
- linked together by peptide bonds
- 20 in existence; each have a different R group
- have an amino group (n terminus), carboxyl group C terminus, R group (side chains)
Facts about nucleotides
- one nitrogen containing rings
- five carbon sugar (ribose or deoxy ribose
- phosphate group
purines= a and g which are double ringed
pyrimidines= c and t and u which has one ring
Metabolism
- all the chemical reactions that occur in the cell
- organize pathways
- pathways are complex and interconnected
- anabolic= building pathways, use energy
- catabolic= breaking down pathways; release energy
1st law of thermodynamics
energy can be transformed from one form to another but can’t be created or destroyed
2nd law of thermodynamics
in the universe the degree of disorder can only increase, all energy transfer causes and increase in disorder
cells are ordered and complex so they have to work around the 2nd law by using energy and expelling energy and disorder to environment in form of heat
How do cells obtain energy through oxidation of organic molecules?
stable chemical energy in food is converted into easily useable forms of energy (ex ATP)
plants= sugars produced by photosynthesis
animals= mixture of molecules that are eaten
What is respiration?
the production of ATP in a series of oxidation steps which basically results in sugars being broken down to CO2
What is photosynthesis?
Occurs in plants and some photosynthetic bacteria in 2 stages
What happens in light reactions?
- energy from sun is capture and produces high energy carrier molecules like ATP,NADPH, NADH
- water is split and O2 is produced
What happens in dark reactions?
Carbon is fixated
- CO2 from air is used to generate sugar using the high energy carrier molecules produced in the light reactions
Free Energy and Chemical Reactions
- All molecules have an energy called Free Energy (G)
- Can be used to do work or drive reactions
- Each chemical reaction occurs with a change in G (delta G)
- A+B –> C+D
- Delta G = free of energy of C+D – free energy of A+B
Spontaneous Reactions
- reactants have more energy than products
- energy is released
- disorder increases
- negative delta G
- energetically favorable
Non-spontaneous reactions
- reactants have less energy than products
- energy is absorbed by reaction
- disorder decreases (against 2nd law of thermodynamics
- positive delta G
- energetically unfavorable
How do cells make energetically unfavorable reactions proceed?
- by coupling unfavorable reactions to favorable reactions
- the overall delta G for the combined reactions is negative and so the set of reactions proceeds spontaneously
Examples of high energy intermediates that allow coupling
- ATP carries a high energy phosphate group
- NADH and NADPH- carry high energy electrons
An example of indirect pathways that uses ATP
non-spontaneous reaction: A-H + B-OH –> A-B + H2O (condensation reaction)
- ) B-OH + ATP –> B-O-PO3 +ADP (favorable; B-O-PO3 is a high energy intermediate)
- ) A-H + B-O-PO3 –> A-B +Pi (favorable)
Net result:
B-OH + ATP + A-H –> A-B + ADP + Pi + H2O
Cells make ATP in two ways:
- Glycolysis (does not required O2)
- Citric Acid Cycle and Electron Transport Chain (require O2)
What are the 3 steps of food break down?
- breakdown of large molecules into simple subunits (mostly outside of cells)
- breakdown of simple subunits into acetyl CoA (production of ATP and NADH)
- occurs mainly in cytosol (glycolysis)
- pyruvate -> acetyl CoA in mitochondria
- occurs mainly in cytosol (glycolysis)
- complete oxidation of acetylCoA to CO2 and H2O
- get production of lots of ATP and NADH
- in mitochondria
- require O2
- citric Acid Cycle and Electron Transport Chain
Stage 2 description
Glycolysis plus pyruvate -> acetyl CoA
Glycolysis (6 carbon) -> pyruvate (3C)
-requires an input of ATP
-net result: 2ATP, 2 pyruvate, 2 NADH
-in cytosol and does not require O2
-pyruvate moves from cytosol to mitochondrial matrix
-pyruvate is converted to acetyl CoA (in matrix)
Stage 3 description
-acetyl CoA enters citric acid (TCA) cycle for every one turn of cycle get: 3NADH, 1 GTP, 1 FADH2, 2 CO2 - two turns per glucose - in mitochondria - requires O2
Electron Transport Chain
- respiratory (protein complexes embedded in inner mitochondrial membrane
- high energy electrons from NADH are passed along chain
- respiratory complexes use energy from e- transfer to pump H+ (protons) across membrane (matrix -> inner membrane space) and creates a H+ gradient
- H+ gradient is used to make ATP (by ATP synthase) from ADP and Pi (30-32 ATP/glucose
