Cells and Multicellular Organisms Flashcards

Flashcards to help review key vocabulary and concepts related to cells and multicellular organisms.

Nucleus

The control center of the cell, containing the cell's DNA.

Mitochondria

The powerhouse of the cell, responsible for generating energy through cellular respiration.

Rough ER

A network of membranes involved in protein synthesis and transport; has ribosomes attached to its surface.

Ribosomes

Sites of protein synthesis.

Smooth ER

A network of membranes involved in lipid synthesis, detoxification, and calcium storage; lacks ribosomes.

Golgi apparatus

Modifies, sorts, and packages proteins and lipids for secretion or transport to other organelles.

Lysosomes

Organelles containing enzymes that break down cellular waste and debris.

Vacuoles

Large, fluid-filled sacs that store water, nutrients, and waste products.

Chloroplasts

Organelles found in plant cells that carry out photosynthesis.

Fluid mosaic model

A model that describes the cell membrane as a fluid mosaic of phospholipids, cholesterol, proteins, and glycoproteins.

Protein channels

Proteins in the cell membrane that facilitate the transport of specific molecules across the membrane.

Phospholipids

Lipids that form the primary structure of the cell membrane, arranging themselves into a bilayer.

Cholesterol

A lipid that helps regulate the fluidity of the cell membrane.

Glycoproteins

Proteins with attached carbohydrate chains that play a role in cell recognition and signaling.

Osmosis

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

Simple diffusion

The movement of molecules from an area of high concentration to an area of low concentration, without the need for energy or assistance from membrane proteins.

Facilitated diffusion

The movement of molecules across the cell membrane with the help of membrane proteins, but without the need for energy.

Active transport

The movement of molecules across the cell membrane against their concentration gradient, requiring energy and the assistance of membrane proteins.

Endocytosis

The process by which cells engulf large particles or droplets by enclosing them in vesicles derived from the cell membrane.

Exocytosis

The process by which cells release large particles or droplets by fusing vesicles with the cell membrane.

Passive transport

Transport that does not require energy.

Hierarchical organization

Cells, tissues, organs, and systems

Prokaryotic cells

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

Eukaryotic cells

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

Unipotent stem cells

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

Multipotent stem cells

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

Pluripotent stem cells

Stem cells that can differentiate into almost any type of cell.

Totipotent stem cells

Stem cells that can differentiate into any type of cell, including embryonic and extraembryonic tissues.

Nephron

The functional units of the kidneys, responsible for filtering waste products from the blood and producing urine.

Glomerulus

A network of capillaries in the nephron where filtration of blood occurs.

Bowman's capsule

A cup-shaped structure in the nephron that surrounds the glomerulus and collects the filtrate.

Proximal tubule

A portion of the nephron where selective reabsorption of water, ions, and nutrients occurs.

Loop of Henle

A U-shaped portion of the nephron that helps concentrate the urine.

Distal tubule

A portion of the nephron where further selective reabsorption and secretion occur.

Collecting duct

A duct in the nephron that collects urine from multiple nephrons and carries it to the renal pelvis.

Glomerular filtration

The movement of substances from the blood into the nephron.

Selective reabsorption

The movement of substances from the nephron back into the blood.

Secretion

The movement of substances from the blood into the nephron for excretion.

Enzymes

Proteins that catalyze biochemical reactions by lowering the activation energy.

Active site

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

Induced-fit model

A model of enzyme function in which the enzyme's active site changes shape to better fit the substrate.

Lock-and-key model

A model of enzyme function in which the enzyme and substrate fit together perfectly, like a lock and key.

Inhibitors

Substances that reduce the activity of enzymes.

Carbohydrates

Macromolecules composed of monosaccharides and disaccharides that provide energy and structural support.

Proteins

Macromolecules composed of amino acids that perform a wide variety of functions, including catalyzing reactions, transporting molecules, and providing structural support.

Lipids

Macromolecules composed of fatty acids that store energy, provide insulation, and form cell membranes.

Amylase

An enzyme that breaks down starch into sugars.

Protease

An enzyme that breaks down proteins into amino acids.

Lipase

An enzyme that breaks down fats into fatty acids and glycerol.

Villi

Small, finger-like projections in the small intestine that increase the surface area for absorption of nutrients.

Metabolism

The sum of all chemical reactions that occur in an organism.

Catabolism

The breakdown of complex molecules into simpler ones, releasing energy.

Anabolism

The synthesis of complex molecules from simpler ones, requiring energy.

ATP

A molecule that stores and transports chemical energy within cells.

Aerobic respiration

A metabolic process that converts glucose into energy in the presence of oxygen.

Glycolysis

The initial stage of cellular respiration, in which glucose is broken down into pyruvate.

Krebs cycle

A series of chemical reactions that extract energy from pyruvate, producing ATP, NADH, and FADH2.

Electron transport chain

A series of protein complexes in the inner mitochondrial membrane that transfer electrons, generating a proton gradient that drives ATP synthesis.

Anaerobic respiration

A metabolic process that converts glucose into energy in the absence of oxygen.

Photosynthesis

Plants convert light energy into chemical energy in the form of glucose.

Light-dependent reactions

The first stage of photosynthesis, in which light energy is captured and converted into chemical energy.

Light-independent reactions

The second stage of photosynthesis, in which carbon dioxide is fixed and converted into glucose.

Xylem

Vascular tissue in plants that Transports water and minerals from the roots to the rest of the plant .

Phloem

Vascular tissue in plants that transports sugars from the leaves to the rest of the plant.

Stomata

Pores on the surface of leaves that facilitate gas exchange.

Guard cells

Cells that surround stomata and regulate their opening and closing.