Biology Unit C: Cellular Respiration and Photosynthesis

photosynthesis

the process by which plants, algae, and some kinds of bacteria use the suns light energy to chemically convert carbon (inorganic) into carbohydrates (organic) such as sugars and starches

chloroplast

organelle within photosynthetic organisms containing the photosynthetic pigment chlorophyll

mitochondria

organelle that breaks down organic molecules, usually carbohydrates, to release energy

cellular respiration

process in which, mitochondria in the cells of plants, animals, and other multicellular organisms break down carbohydrates and other energy rich products derived from them, such as fats, to generate molecules of ATP

thylakoid

interconnected flattened sac within the stroma of a chloroplast; membranes contain chlorophyll may occur in a stack called granum

reducing power

the chemical potential energy available in molecules that are in their reduced form

passive transport

no energy required; molecules move independently of each other down a concentration gradient

diffusion

a process in which molecules move from areas of high concentration to low concentration

facilitated diffusion

a process in which larger molecules need the help of proteins in cell walls to move from areas of high concentration to low concentration

osmosis

the diffusion of water across a semipermeable membrane

active transport

a process that requires energy from ATP to move substances against the concentration gradient

endocytosis

a process in which cell membranes engulf a substance and pinch off inside the cell

pinocytosis

a process in which the cell wall engulfs liquids and their solutes and pinches off inside the cell

phagocytosis

a process in which the cell wall engulfs a large particle, such as bacteria or a blood cell, and pinches off inside of the cell

exocytosis

a process in which a vacuole containing substances from inside a cell (cytoplasm) fuses with the cell wall and the contents are released outside of the cell

nucleus

the command centre of the cell that contains the DNA blueprints for making proteins and is surrounded by a double membrane to protect the DNA from potentially damaging byproducts of biochemical reactions

nuclear pores

pores in the nuclear membrane large enough to allow macromolecules to enter and ribosomes to leave the nucleus

chromatin

uncoiled chromosomes (DNA)

nucleolus

a specialized area of chromatin inside the nucleus responsible for producing ribosomes

nuclear envelope

the double membrane that surrounds a cell’s nucleus and controls what enters and leaves the nucleus.

ribosome

tiny two-part structures found throughout the cytoplasm that help put together proteins

endoplasmic reticulum (ER)

a system of flattened membrane-bound sacs and tubes continuous with the outer membrane of the nuclear envelope that has two types of membrane

rough ER

studded with ribosomes and synthesizes proteins

smooth ER

synthesizes phospholipids and packages macromolecules in vesicles for transports to other parts of the cell

cell membrane

a structure that separates the cell interior from the outside world and controls the movement of materials into and out of the cell

cell wall

a rigid structure surrounding the cell membrane that protects and supports the cell and allows materials to pass to and from the cell membrane through pores

cytoplasm

a gel-like material consisting mostly of water that contains dissolved materials and creates the chemical environment in which the other cell structures work

Golgi apparatus

a stack of flattened membrane-bound sacs that receive vesicles from the ER, contain enzymes for modifying proteins and lipids, package finished products into vesicles for transport to the cell membrane (for secretion out of the cell) and within the cell as lysosomes

microtubule

a microscopic tubular structure present in numbers in the cytoplasm of cells, sometimes aggregating to form more complex structures.

vacuole

a large membrane-bound, fluid-filled sac for the temporary storage of food, water, or waste products

peroxisome

a membrane-bound vesicle containing enzymes that break down lipids and toxic waste products, such as alcohol

vesicle

a small membrane-bound transport sac

cytoskeleton

a network of three kinds of interconnected fibres that maintain cell shape and allow for movement of cell parts: actin filaments, intermediate filaments, and microtubules

lysosome

a membrane-bound vesicle filled with digestive enzymes that can break down worn-out cell components or materials brought into the cell

centrosome

small structure in animal cells that organizes microtubules and helps the cell divide by forming the spindle that separates chromosomes.

metabolism

all of the chemical reactions that occur within a cell to support and sustain its life functions

catabolic

compound-decomposing metabolic reaction

anabolic

compound-synthesizing metabolic reaction

ATP (adenosine triphosphate)

a high-energy phosphate molecule that provides and stores the energy required for cellular functions

oxidation

a loss of electrons

proton

a hydrogen atom which has a lost an electron

redox reaction

a reaction involving the transfer of electrons

reduction

a gain of electrons

chemiosmosis

the process by which ATP is generated through the movement of protons down a concentration gradient

NADP+

nicotinamide adenine dinucleotide phosphate in its oxidized state (has lost an electron)

NADPH

nicotinamide adenine dinucleotide phosphate in its reduced state; used in light-independent reactions to form glucose

photosystem

a cluster of light-absorbing pigment molecules in the thylakoid membrane of chloroplasts

reference flow

a measure of how far a substance molecule is transported in chromatography

thylakoid membrane

flattened stacks within the stroma that contain chlorophyll

calvin-benson cycle

the process in which photosynthetic organisms fix carbon from atmospheric carbon dioxide to produce carbohydrates like glucose.

carbon dioxide fixation

a carbon atom in carbon dioxide is chemically bonded to a pre-existing 5-carbon compound in the stroma of the chloroplast

glucose

a saccharide or sugar; can be linked to many other saccharides to form different types of sugars or carbohydrates

phosphoglyceraldehyde (PGAL)

a high-energy compound used to make glucose

ribulose biphosphate (RuBP)

a 5-carbon molecule in the stroma that initially bonds to carbon dioxide in the Calvin-Benson cycle

grana

stack of chlorophyll-containing thylakoids within a chloroplast

stroma

fluid in the inner space of a chloroplast, which contains a concentrated mixture of proteins and other chemicals that are used in the synthesis of carbohydrates during photosynthesis

ATP synthase

an enzyme that makes ATP, the main energy-carrying molecule in cells, by using the flow of ions across a membrane.

electron transport system

in mitochondria and chloroplasts, a system of electron-carrying molecules that transfer electrons to generate a hydrogen ion gradient across a thylakoid or inner mitochondrial membrane to produce ATP

glycolysis

a metabolic pathway in which one glucose molecule is broken down to form two, 3-carbon molecules and a small amount of ATP. Glycolysis is the first step in both anaerobic and aerobic respiration.

pyruvate

three-carbon molecules produced by glycolysis

phosphorylation

the process of adding a phosphate to a molecule to activate it; occurs in at the onset of cellular respiration

aerobic cellular respiration

respiration carried out using oxygen to produce ATP

anaerobic cellular respiration

respiration carried out without using oxygen to produce ATP

Krebs cycle

a metabolic pathway consisting of a series of reactions that break down the end products of glycolysis, producing carbon dioxide and generating a large amount of ATP

fermentation

energy-yielding metabolic pathway in which carbohydrates are anaerobically broken down into simpler components; includes glycolysis and is widely occurring in yeast and bacteria

pyruvate

three-carbon molecules produced by glycolysis

phosphorylation

the process of adding a phosphate to a molecule to activate it; occurs in at the onset of cellular respiration

acetyl CoA

a molecule formed from a coenzyme and a 2-carbon molecule which is used to start the Krebs cycle

FADH₂

an important coenzyme produced during the Krebs cycle

NADH

a high-energy electron carrier 

biogas

methane captured from animal waste that is used as fuel

biofuel

ethanol produced during the fermentation of biomass

VO₂ max

used to measure how well an athlete is able to use oxygen during an activity;  units are mL/kg/min