Cell and Energy systems (Week 1 )

Plasma Membrane

The outside layer of a cell that regulates the movement of substances.

Nucleus

The control centre of the cell.

Cytoskeleton

Protein fibres that extend through the cytoplasm and act as the skeleton of the cell.

Mitochondria

Known as the powerhouse of the cell.

Ribosomes

Cellular structures that build proteins.

Endoplasmic Reticulum

The transport system within a cell for proteins and lipids.

Golgi Apparatus

The structure that receives and sorts proteins.

Diffusion

The movement of small molecules, such as Oxygen, from HIGH concentration to LOW concentration using kinetic energy.

Osmosis

The movement of Water from HIGH concentration to LOW concentration through a semi-permeable membrane.

ATP PCr

Adenosine Triphosphate Phosphocreatine System; a quick releasing energy system used for bursts of exercise lasting less than $20\text{sec}$.

Creatine kinase

The enzyme used to recharge ADP into ATP by donating a phosphate.

Anaerobic Glycolysis

An energy system occurring in the cell cytoplasm that utilizes glucose to produce pyruvate (lactic acid) without oxygen, yielding a net of $2$ ATP.

Aerobic System

The primary energy system for long duration exercise that utilizes oxygen and produces approximately $30-32$ ATP.

Acetyle coenzyme a

The substance formed when pyruvate becomes oxidised before entering the krebs cycle.

Krebs cycle

A stage of aerobic metabolism that extracts energy and produces high energy electron carriers such as NADH and FADH.

Electron transport chain

The process that changes NADH and FADH into ATP through the movement of electrons, resulting in carbon dioxide and water as end products.

Metabolism

The chemical processes occurring within a living cell or organism that are necessary for the maintenance of life, categorized into catabolism and anabolism.

Adenosine triphosphate (ATP)

The primary energy currency of the cell, consisting of adenine, ribose, and three linked phosphates.

ATP Synthesis

The chemical reaction where adenosine diphosphate combines with inorganic phosphate to form ATP: $ADP + Pi \rightarrow ATP$.

ATP Breakdown

The hydrolysis reaction that releases energy for cellular work: $ATP \rightarrow ADP + Pi + \text{Energy}$ via the enzyme ATPase.

Enzymes

Catalysts that regulate the speed of chemical reactions by lowering the energy of activation; their activity is regulated by temperature and pH.

Lock-and-key model

A model describing the specific interaction between enzymes and their substrates.

Carbohydrate (CHO) fuel stores

Substrates stored as glucose or as glycogen in the muscle and liver.

Fat fuel stores

Substrates stored as free fatty acids (FFA) or as triglycerides in muscle and fat cells.

ATP-PCr System Power and Capacity

Energy system with a power of $3.6 \text{ mM ATP/min}$ and a capacity of $0.7 \text{ Total mol ATP}$.

Glycolytic System Power and Capacity

Energy system with a power of $1.6 \text{ mM ATP/min}$ and a capacity of $1.2 \text{ Total mol ATP}$.

Aerobic System Power and Capacity

Energy system with a power of $1.0 \text{ mM ATP/min}$ and a capacity of $90.0 \text{ Total mol ATP}$ (from glycogen).

Phosphocreatine (PCr or CP)

A rapid source of ATP that undergoes hydrolysis to make ATP via the reaction: $PCr + ADP \rightarrow ATP + Cr$ mediated by Creatine kinase.

Glycolysis

An anaerobic process occurring in the cytoplasm where glucose is broken down into 2 pyruvate or 2 lactate, producing a net of 2 ATP and 2 $(NADH + H^+)$ molecules.

Lactate

The conjugate base of lactic acid produced during glycolysis.

Anaerobic pathways

Energy systems (ATP-PCr and Anaerobic glycolysis) that do not use oxygen, occur in the cytosol, and produce relatively quick but lesser amounts of energy.

Krebs Cycle

A series of aerobic reactions in the mitochondrial matrix involving the oxidation of the carbon skeleton of fuel to $CO_2$ and the formation of $(NADH + H^+)$, $FADH_2$, and some ATP.

Nicotinamide adenine dinucleotide (NAD)

A reducing equivalent that exists in an oxidized form ($NAD^+$) and a reduced form ($NADH$), playing an important role in electron transfer.

Flavin adenine dinucleotide (FAD)

A reducing equivalent that exists in an oxidized form ($FAD$) and a reduced form ($FADH_2$), playing an important role in electron transfer.

Electron transport system (respiratory chain)

Reactions in the inner mitochondrial membrane where electrons from $(NADH + H^+)$ and $FADH_2$ are transported to $O_2$ to form $H_2O$.

Oxidative phosphorylation

Aerobic reactions in the inner mitochondrial membrane where ATP synthesis is coupled to electron transport, mediated via $H^+$ through ATP synthase (chemiosmotic hypothesis).

Oxidative phosphorylation yield

The specific ATP yield where 1 $(NADH + H^+)$ yields 3 ATP and 1 $FADH_2$ yields 2 ATP.

Glucose ATP Yield

The total ATP production from the complete oxidation of one glucose molecule: $C_6H_{12}O_6 \rightarrow 6 CO_2 + 6 O_2 + 36-38 \text{ ATP}$.

Which structure serves as the selectively permeable boundary of the cell?

The Plasma Membrane

What is the term for the movement of substances from an area of high concentration to an area of low concentration?

Diffusion

What category of transport does not require the expenditure of metabolic energy (ATP)?

Passive Transport

What is the specific term for the diffusion of water across a semi-permeable membrane?

Osmosis

What model describes the membrane as a dynamic structure composed of proteins floating in a lipid bilayer?

The Fluid Mosaic Model

Which type of transport mechanism moves molecules against their concentration gradient?

Active Transport

In the sodium-potassium pump cycle, how many sodium ions are transported out of the cell?

$3\,Na^+$ ions

In the sodium-potassium pump cycle, how many potassium ions are transported into the cell?

$2\,K^+$ ions

What is the process known as 'cell eating,' where the membrane engulfs large solid particles?

Phagocytosis

What is the process called when a vesicle fuses with the membrane to release its contents outside the cell?

Exocytosis

Which part of the phospholipid molecule is polar and 'water-loving'?

The Hydrophilic Phosphate Head

Which part of the phospholipid molecule is non-polar and 'water-fearing'?

The Hydrophobic Fatty Acid Tails

What lipid molecule is embedded in the bilayer to modulate membrane fluidity?

Cholesterol

How would you describe a solution where the cell will swell due to water influx?

Hypotonic

How would you describe a solution where the cell will shrink due to water loss?

Hypertonic

What is the term for diffusion that requires a carrier or channel protein to move large or polar molecules?

Facilitated Diffusion

What do we call membrane proteins that span the entire width of the lipid bilayer?

Integral Proteins

What term refers to the combined influence of the concentration gradient and the electrical gradient?

Electrochemical Gradient

What is the process commonly known as 'cell drinking'?

Pinocytosis

What is the primary chemical energy source used to power primary active transport?

ATP (Adenosine Triphosphate)

Which organelle is responsible for generating the majority of the cell's ATP supply?

Mitochondria

Can small, non-polar molecules like oxygen ($O_2$) pass directly through the lipid bilayer?

Yes, via simple diffusion

What type of membrane protein is attached to either the interior or exterior surface rather than embedded inside?

Peripheral Protein