Cell Membranes
What does a biological membrane do?
Separates a cell from its external environment
What is energy?
Capacity to do work (change in state or motion of matter)
expressed in kilojoules or kilocalories
What are the 4 stages of cellular respiration?
Glycolysis
Formation of Acetyl CoA
Krebs Cycle / Citric Acid Cycle
Electron Transport Chain
What is photosynthesis?
The process by which plants convert light energy into chemical energy
What is the difference between oxidation and reduction?
Oxidation: loss of electrons
Reduction: gain of electrons
*can remember "OIL RIG" or "LEO goes GER"
What is the structure of the cellular membrane made of?
Phospholipids that form a bilayer with the hydrophilic tails on the inside and the hydrophilic heads facing the aqueous environment
What are the two processes of metabolism?
Anabolism: synthesizing molecules
Catabolism: breaking molecules down
What happens in glycolysis?
Glucose is broken down into two pyruvate molecules
What are photons?
Small particles or packets that compose light
What are enzymes?
Proteins that act as biological catalysts, speeding up essential chemical reactions in living organisms without being consumed by the reaction. They work by lowering the activation energy required for a reaction to occur.
What is cholesterol?
Molecule that keeps animal membranes fluid at low temperatures and stable at high temperatures.
What is the 1st Law of Thermodynamics?
Energy cannot be created or destroyed, only transformed or converted to another form.
What is the major event that occurs in the Krebs Cycle?
Complete oxidation of acetyl CoA, releasing 1 ATP, 3 NADH, and 1 FADH2, and 2 CO2 per acetyl CoA molecule
During photosynthesis, what gas is taken in from the environment to incorporate into organic molecules?
CO2
What are the 3 concentration conditions of osmosis?
Isotonic: no net movement of water molecules
Hypertonic: higher concentration of solutes exists outside the cell; cell loses water and shrivels
Hypotonic: lower concentration of solut outside cell; cell gains water and swells
What is diffusion, and which way does it occur?
Movement of particles from an area of high concentration to an area of low concentration
What are redox reactions?
Reactions that involved the transfer of electrons between atoms or molecules
What happens in the electron transport chain?
electrons from NADH and FADH2 are transferred to oxygen, creating a proton gradient and resulting in the production of ATP through oxidative phosphorylation
What is the pigment inside the thylakoid membrane that absorbs light primarily in the blue and red regions of the visible spectrum?
Chlorophyll
What does ATP synthase do?
Synthesizes ATP from ADP and P(i) by utilizing energy generated from the proton gradient in the ETC
*ATP stores most energy in these phosphate bonds
What are the types of membrane proteins?
Integral membrane proteins: amphipathic proteins firmly bound to the membrane
Transmembrane proteins: integral proteins that extend completely through the membrane
Peripheral membrane proteins: located on inner or outer surface of palsma membrane, bound to exposed regions of integral proteins
What is the difference between exergonic and endergonic reactions?
Exergonic: releases energy and occurs spontaneously
Endergonic: requires energy input to occur (non-spontaneous)
Theoretically, how much ATP is formed from each stage of the Krebs cycle per glucose molecule ?
Glycolysis: 2 ATP
Krebs Cycle: 2 ATP
electron transport chain: 34 ATP
What is a stromata?
Microscopic pores of leaf where gas exchange occurs
What is the difference between photoautotrophs, chemoheterotrophs, photoheterotrophs, chemoautotrophs.
Photoautotrophs use light energy to make organic molecules from CO₂
Chemoheterotrophs obtain both energy and carbon from organic molecules
Photoheterotrophs use light for energy but need organic compounds for carbon
Chemoautotrophs use inorganic chemicals for energy and CO₂ as their carbon source.