Year 11 Biology Revision Unit 1

Vocabulary terms and definitions from the Unit 1 Biology revision notes covering cell biology, transport, digestion, the urinary system, respiration, photosynthesis, and plant transport.

Prokaryotes

Simple and original cells that are small, lack membrane-bound organelles, and contain circular DNA concentrated in the nucleoid.

Eukaryotes

Larger, complex cells containing membrane-bound organelles and DNA coiled into chromosomes within a nucleus; includes smooth muscle and plant epidermis cells.

Golgi Apparatus

An organelle that packages vesicles for exocytosis (leaving the cell) and unpacks vesicles transporting materials from outside the cell.

Nucleus

The organelle that stores genetic information and serves as the site for DNA replication and RNA transcription from a DNA template.

Rough Endoplasmic Reticulum

A part of the Endoplasmic Reticulum that has ribosomes and is involved in protein synthesis.

Smooth Endoplasmic Reticulum

A part of the Endoplasmic Reticulum involved in lipid and carbohydrate synthesis.

Mitochondria

The site of cellular respiration where glucose is broken down into energy usable by the cell and where gas exchange of $O_2$ and $CO_2$ occurs.

Plasma Membrane

A semi-permeable double layer of fats studded with proteins that assist in transport and cell-cell recognition.

Diffusion

The passive process where molecules or ions spread from regions of higher concentration to regions of lower concentration.

Facilitated Diffusion

A type of passive transport where large, polar, or charged molecules move through membrane proteins from high to low concentration.

Osmosis

The movement of water molecules across a selectively permeable membrane from an area of high concentration to an area of low concentration.

Hypertonic Solution

A condition with high solute concentration and low osmotic potential, resulting in a net flow of water into the cell.

Hypotonic Solution

A condition with low solute concentration and high osmotic potential, resulting in a net flow of water out of the cell.

Exocytosis

The secretion of biological molecules where a vesicle from the Golgi Apparatus fuses with the plasma membrane to spill contents outside the cell.

Endocytosis

The process of intake of biological molecules by the formation of vesicles from the plasma membrane.

Phagocytosis

A process where a cell engulfs a particle, which is then digested by fusing with a lysosome.

Surface Area to Volume Ratio (SA:V)

A ratio that dictates a cell's ability to efficiently exchange nutrients and waste; it decreases as a cell grows.

Mechanical Digestion

The physical breakdown of food into smaller pieces by crushing or cutting, such as through teeth or peristalsis.

Chemical Digestion

The use of enzymes and hydrolysis to break down complex organic food molecules into simple molecules.

Lipase

An enzyme in the stomach that breaks down fats (lipids) into fatty acids and glycerol.

Protease

An enzyme in the stomach that breaks down proteins into amino acids.

Amylase

An enzyme in saliva that breaks down starch into sugars.

Villi

Finger-like projections on the inner surface of the ileum that increase surface area for nutrient absorption.

Assimilation

The incorporation of nutrients into the body, including the conversion of excess amino acids into urea or glucose.

Nephron

The functional unit of the kidney that filters blood, produces urine, and regulates sodium salts and water; approximately $1000000$ per kidney.

Glomerulus

A structure in the nephron where waste (nitrogenous and water) filters into the Bowman's Capsule.

Loop of Henle

A part of the nephron involved in reabsorption; the descending limb pulls water out passively while the ascending limb actively pulls $Na$ and $Cl$ out.

Antidiuretic Hormone (ADH)

A hormone released when dehydrated to add aquaporins to the collecting duct, allowing water to diffuse into the blood stream.

Enzymes

Proteins that act as catalysts to speed up chemical reactions by lowering the activation energy needed.

Denaturation

A change in the shape of an enzyme protein that destroys its function, typically occurring at temperatures above $50$ degrees.

Pulmonary Circulation

The circuit through the lungs where deoxygenated blood becomes oxygenated.

Systemic Circulation

The circuit of blood flow throughout the rest of the body.

Hemoglobin

A protein in red blood cells with a high affinity for oxygen that forms oxyhaemoglobin through a weak bond.

Adenosine Triphosphate (ATP)

A molecule consisting of adenine, ribose, and three phosphate groups that serves as transportable and readily accessible stored energy.

Cellular Respiration Equation

$$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$$

Aerobic Respiration

A long-duration process requiring $O_2$ that produces $CO_2$, $H_2O$, and a high energy yield of $30$ to $32$ ATP.

Anaerobic Respiration

A fast process not requiring $O_2$ that produces lactic acid (in animals) or ethanol and $CO_2$ (in plants/fungi), yielding $2$ ATP.

Glycolysis

The first stage of respiration occurring in the cytoplasm where glucose is broken down into pyruvate, producing a net gain of $2$ ATP.

Krebs Cycle

A stage of aerobic respiration in the mitochondrial matrix that produces $2$ ATP and loaded electron carriers, releasing $CO_2$ as waste.

Electron Transport Chain (ETC)

The final stage of aerobic respiration in the inner mitochondrial membrane that uses oxygen to yield approximately $32-34$ ATP.

Photosynthesis Equation

$$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$$

Thylakoids

Membranous sacs in chloroplasts stacked into grana where the light-dependent reactions and chlorophyll are located.

RuBisCo

The enzyme in the stroma that 'fixes' carbon dioxide to RuBP during the light-independent reactions (Calvin Cycle).

Stomata

Pores mostly on the underside of leaves that open (when turgid) to allow water and gas exchange.

Xylem

A vascular tissue made of hollow dead cells that transports water and minerals in a one-way upward flow using negative pressure.

Phloem

A vascular tissue made of live cells that transports sugars, amino acids, and hormones in a two-way flow using osmosis and turgor pressure.

Translocation

The movement of organic molecules such as sugars and amino acids through the sieve tubes of the phloem.

Cohesion

The property of water molecules being attracted to each other, aiding their movement up the xylem.

Adhesion

The property of water molecules being attracted to the walls of the xylem.