Cells as the Basis of Life, Exchange of Nutrients, and Plant Physiology

Flashcards covering prokaryotic and eukaryotic cell biology, cellular transport, enzyme function, organ system hierarchies, metabolism, and plant physiology based on the science exam checklist.

Prokaryotic cells

Cells that lack a nucleus and other membrane-bound organelles.

Eukaryotic cells

Cells that contain a nucleus and various membrane-bound organelles.

Nucleus

A key organelle responsible for containing the cell's genetic material.

Mitochondria

The organelle responsible for aerobic respiration and the production of ATP.

Rough ER

Rough endoplasmic reticulum; an organelle studded with ribosomes involved in protein synthesis and transport.

Ribosomes

Organelles that are the primary sites of protein synthesis.

Smooth ER

Smooth endoplasmic reticulum; an organelle involved in lipid synthesis and detoxification.

Golgi apparatus

An organelle that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

Lysosomes

Organelles containing digestive enzymes to break down waste materials within the cell.

Vacuoles

Storage organelles used for holding water, nutrients, or waste products.

Chloroplasts

Organelles found in plants that are the site of photosynthesis.

Surface area-to-volume ratio ($SA:V$ ratio)

The relationship between a cell's surface area and its volume, which limits cell size and affects the rate of diffusion.

Stem cells

Undifferentiated cells that originate through mitosis and can differentiate into specialised cells.

Unipotent stem cells

Stem cells that can only differentiate into one specific cell type.

Multipotent stem cells

Stem cells that can differentiate into a limited range of related cell types.

Pluripotent stem cells

Stem cells capable of differentiating into many, but not all, cell types.

Totipotent stem cells

Stem cells that have the potential to differentiate into any cell type, including embryonic and extra-embryonic tissues.

Fluid mosaic model

A model describing the cell membrane structure as a mosaic of protein channels, phospholipids, cholesterol, and glycoproteins.

Osmosis

The passive movement of water across a semipermeable membrane from an area of low solute concentration to high solute concentration.

Simple diffusion

The passive movement of substances directly through the cell membrane from an area of high concentration to an area of low concentration.

Facilitated diffusion

The passive movement of substances across a membrane via specific protein channels or carriers.

Protein-mediated active transport

The movement of substances across a membrane against its concentration gradient using energy and specific membrane proteins.

Endocytosis

The process by which a cell takes in materials by engulfing them in an energy-dependent membrane vesicle.

Exocytosis

The process by which a cell releases materials in vesicles that fuse with the cell membrane, requiring energy.

Active transport

The movement of substances across a cell membrane that requires the expenditure of cellular energy (ATP).

Passive transport

Movement of substances across a cell membrane without the use of cellular energy.

Carbohydrates

Macromolecules used by organisms for energy and structural purposes.

Proteins

Complex molecules made of amino acids that perform structural, enzymatic, and transport functions.

Lipids

Molecules used for long-term energy storage and as components of the cell membrane.

Enzymes

Biological catalysts that control and regulate metabolic processes like digestion.

Active site

The specific region of an enzyme where the substrate binds and the chemical reaction occurs.

Induced-fit model

A model of enzyme action where the active site undergoes a slight change in shape to better fit the substrate.

Lock-and-key model

A model of enzyme action where the substrate fits perfectly and specifically into a rigid active site.

Villi

Structural features in the digestive system of mammals that provide a large surface area for efficient nutrient exchange.

Capillaries

Small blood vessels that serve as exchange surfaces for nutrients and gases in the circulatory system.

Closed circulatory system

A system where blood is contained within vessels to facilitate efficient transport of materials to and from all body cells.

Nephron

The functional unit of the kidney involved in the production of urine.

Glomerulus

A bundle of capillaries in the nephron where blood is filtered.

Bowman’s capsule

The cup-like structure in the nephron that collects filtrate from the glomerulus.

Proximal tubule

The section of the nephron following the Bowman's capsule where selective reabsorption occurs.

Loop of Henle

A loop in the nephron involved in the reabsorption of water and salts to concentrate urine.

Distal tubule

A part of the nephron between the Loop of Henle and the collecting duct involved in the selective reabsorption and secretion of ions.

Collecting duct

The final part of the nephron where urine is collected and further concentrated before exiting.

Glomerular filtration

The process of filtering waste from the blood through the membrane of the glomerulus.

Selective reabsorption

The process where the nephron recovers useful substances like glucose and water from the filtrate back into the blood.

Catabolism

The metabolic process of breaking down complex molecules into simpler ones to release energy.

Anabolism

The metabolic process of building complex molecules from simpler ones, requiring energy.

ATP

Adenosine Triphosphate; the molecule that transfers energy from catabolic reactions to anabolic reactions.

Aerobic respiration

The process of producing energy using oxygen, described by: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + 36\text{--}38\,ATP$.

Glycolysis

The first stage of cellular respiration that occurs in the cytoplasm of the cell.

Krebs cycle

A series of reactions in aerobic respiration that occurs in the mitochondria.

Alveoli

Tiny air sacs in the lungs where gas exchange occurs between the respiratory and circulatory systems.

Photosynthesis

The process of converting light energy into chemical energy, described by: $6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2$.

Light-dependent reactions

The first stage of photosynthesis that requires light energy to occur.

Light-independent reactions

The second stage of photosynthesis that does not directly require light to produce glucose.

Xylem

Plant vascular tissue that transports water and dissolved minerals from the roots upwards.

Phloem

Plant vascular tissue responsible for the transport of sugars and other nutrients from leaves to other parts of the plant.

Stomata

Pores on the surface of plant leaves through which gas exchange occurs.

Guard cells

Pairs of cells that surround stomata and regulate their opening and closing.

Transpiration

The process of water movement through a plant and its evaporation from aerial parts, such as leaves.