cells 1

Comprehensive vocabulary flashcards covering cell transport mechanisms, enzyme kinetics and models, cellular respiration, photosynthesis phases and organelles, as well as mitosis and DNA replication.

Passive Transport

The movement of materials across a cell membrane from an area of high concentration to an area of low concentration without the use of energy.

Diffusion

The movement of materials from an area of higher concentration to an area of lower concentration.

Osmosis

The movement of water across a semi-permeable membrane from an area of higher water potential to an area of lower water potential.

Facilitated Diffusion

The movement of materials that cannot cross the phospholipid bilayer on their own (such as glucose, amino acids, sodium, and chloride ions) through protein channels and carrier proteins embedded in the plasma membrane.

Active Transport

The movement of materials across a cell membrane against their concentration gradient (from low to high concentration) using energy in the form of ATP.

Ion Pumps

Plasma membrane proteins that change shape to force or pump ions (such as $Na^+$ and $K^+$) across the membrane against their concentration gradient.

Endocytosis

A process where materials that are too large to diffuse through the membrane are engulfed within the cell membrane, forming a membrane-bound sac or vesicle.

Phagocytosis

A type of endocytosis in which solid materials are engulfed and transported into the cell.

Pinocytosis

A type of endocytosis in which liquid materials are engulfed and transported into the cell.

Exocytosis

The process of moving substances out of a cell using vesicles.

Tonicity

The relative concentration of solutes on either side of the cell membrane, which determines the direction and extent of water movement.

Hypertonic Solution

A solution with a higher concentration of solutes outside the cell than inside, causing water to move out of the cell due to lower water concentration outside.

Hypotonic Solution

A solution with a lower concentration of solutes outside the cell than inside, causing water to move into the cell due to higher water concentration outside.

Isotonic Solution

A solution with the same solute concentration inside and outside the cell, resulting in equal rates of water molecules entering and leaving the cell.

Enzymes

Biological molecules that act as biological catalysts, speeding up chemical reactions by lowering the activation energy needed to start them.

Lock and Key Model

A model of enzyme action where the enzyme has a rigid active site that fits the substrate precisely like a key in a lock to form an enzyme-substrate complex.

Induced Fit Model

A model of enzyme action where the active site bends slightly and moulds itself around the substrate to create an optimal, precise fit before releasing products and returning to its original shape.

Enzyme Denaturation

The process where excessive heat or extreme pH breaks the bonds holding an enzyme together, changing the active site shape so the substrate can no longer fit.

Cofactor

A non-protein compound required for an enzyme to function properly, generally sitting in the active site to assist substrate binding.

Competitive Inhibitors

Substances that bind directly to the active site of an enzyme, preventing the substrate from binding.

Non-competitive Inhibitors

Substances that bind to a regulatory region of an enzyme, altering the active site's shape so the substrate cannot bind effectively.

Respiration

A chemical process where organisms use glucose and sometimes oxygen to produce energy in the form of ATP, as well as carbon dioxide and water.

Stage 1 of Respiration

An aerobic or anaerobic process occurring in the cytoplasm where glucose is broken down by specific enzymes into $2$ pyruvate, $2$ ATP, and $2$ NADH.

Mitochondrial Matrix

The internal compartment of the mitochondrion housing enzymes for Stage 2 of respiration, providing a contained environment with optimal pH conditions for efficient reactions.

Mitochondrial Cristae

Folds of the inner mitochondrial membrane that provide a large surface area for Stage 3 respiration reactions, enabling faster ATP production per unit of time.

Photosynthesis

A series of enzyme-controlled reactions that convert light energy into chemical potential energy (glucose) and oxygen.

Light-Dependent Phase (Stage 1 Photosynthesis)

The phase occurring in the thylakoid membrane where chlorophyll absorbs light energy to split water into hydrogen and oxygen, producing a small amount of ATP and NADPH while releasing $O_2$ as waste.

Light-Independent Phase (Stage 2 Photosynthesis)

The phase occurring in the stroma where NADPH enters and hydrogen ions combine with $CO_2$ in a series of reactions to form glucose.

Thylakoid

A membrane structure in chloroplasts containing chlorophyll to absorb light; stacked into grana to maximize surface area for Stage 1 reactions.

Stroma

The clear fluid inside chloroplasts that allows light to reach the thylakoids and contains the enzymes and $CO_2$ required for Stage 2 reactions.

Mitosis

A cell division process where a single parent cell divides to produce two genetically identical diploid daughter cells for growth, repair, and regeneration.

Prophase

The stage of mitosis where newly copied DNA condenses into chromosomes consisting of $2$ identical sister chromatids, the nuclear membrane breaks down, and spindle fibres form.

Metaphase

The stage of mitosis where chromosomes align along the middle (equator) of the cell and spindle fibres attach.

Anaphase

The stage of mitosis where sister chromatids are pulled apart by spindle fibres and separate to opposite poles.

Telophase

The stage of mitosis where chromatids reach opposite poles, nuclear membranes reform around each set of chromosomes, and DNA un-condenses.

Cytokinesis

The physical splitting of the whole cell following mitosis to produce two genetically identical diploid daughter cells.

DNA Replication

The process occurring during interphase where a cell creates an exact copy of its DNA before division to ensure each daughter cell receives a complete set.

DNA Helicase

The enzyme responsible for unwinding the DNA double helix and breaking hydrogen bonds between base pairs to expose both strands during DNA replication.

DNA Polymerase

The enzyme that joins free nucleotides from the nucleus to exposed base pairs, building a new DNA strand in the $5'$ to $3'$ direction.

Okazaki Fragments

Short sections of DNA synthesized on the lagging strand during DNA replication because DNA strands are anti-parallel and DNA polymerase can only build in the $5'$ to $3'$ direction.