Module 1- cell structure and diversity Flashcards
Active transport
The movement of a substance across a cell membrane against its concentration
or electrochemical gradient, mediated by specific transport proteins and
requiring an expenditure of energy.
ATP
Adenosine Triphosphate: An adenine-containing nucleoside triphosphate that
releases free energy when its phosphate bonds are hydrolyzed (broken by
chemical reactions).
Aerobic respiration
A catabolic pathway for organic molecules, using oxygen O2 as the final electron acceptor in an electron transport chain and ultimately producing ATP (as well as carbon dioxide and water).
This is the most efficient catabolic pathway and is carried out in most eukaryotic cells and many prokaryotic organisms.
Amino Acid
An organic molecule serving as the monomer of polypeptides. The building blocks of proteins and macromolecules that carry out biological processes.
Archaea
One of two taxonomic prokaryotic domains having archaeal rRNA sequences, the other being Bacteria
Bacteria
Prokaryotic microorganisms typically having cell walls of peptidoglycan.
Biomolecule
A molecule or ion that is involved in the biological processes (e.g. cell division, development) of living organisms.
Carbohydrate
A sugar (monosaccharide), double sugar (disaccharide) or polysaccharide (multiple bonded sugar molecules)
Calvin Cycle
The second of two major stages in photosynthesis (following the light reactions) involving the fixation of atmospheric carbon dioxide and reduction of the fixed carbon into carbohydrate
Cell
A fundamental part of the living system, cells are the smallest collection of matter that perform all activities required for life. All organisms are made up of cells
Cellular respiration
The catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP
Cellulose
A structural polysaccharide of plant cell walls, consisting of glucose monomers (identical bonded molecules) joined by b glycosidic linkages (a type of bond joining carbohydrate molecules to another group).
Central vacuole
A large membrane-enclosed organelle present in many plant cells; helps maintain turgor pressure of the plant cell, plays a limited storage role, and is also capable of a lysosome-like function in intracellular digestion
Chemiosmosis
An energy coupling mechanism that uses stored energy to drive cellular work, such as ATP synthesis.
Chloroplasts
An organelle found in plants and photosynthetic protists (eukaryotic organism that is not an animal, plant or fungi). Absorbing sunlight for use in photosynthesis.
Chromosome
A cellular structure consisting of one DNA molecule and associated protein
molecules
Chromatin
The complex of DNA and proteins making up eukaryotic chromosomes.
When the cell is not dividing, chromatin exists in its dispersed form, as a mass of very long, thin fibres that are not visible with a light microscope.
Citric acid cycle
A chemical cycle which oxidises acetyl CoA to carbon dioxide, completing the metabolic breakdown of glucose. Occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotes; together with pyruvate oxidation, the second major stage in cellular respiration. Sometimes called the Krebs cycle.
Collagen
A glycoprotein in the extracellular matrix of animal cells that forms strong fibres found extensively in connective tissue and bone
Constitutive secretion
In relation to secretory pathways, constitutive is defined as continuous.(occurring all the time) and is not influenced by external factors or signals.
Co-transport
The coupling of the “downhill” diffusion of one substance to the “uphill” transport of another against its own concentration gradient.
Covalent bond
A type of strong chemical bond in which two atoms share one or more pairs of valence (electrons in the outermost shell) electrons.
Cytoplasm
The contents of the cell bounded by the plasma membrane, excluding the nucleus.
Cytosol
The semifluid portion of the cytoplasm
Cytoskeleton
A network of microtubules, microfilaments, and intermediate filaments that extend through the cytoplasm to serve a variety of functions (mechanical, transport, signalling).
Desmosome
A type of intercellular junction in animal cells, functioning as a rivet, fastening cells together
DNA
Deoxyribonucleic Acid: A nucleic acid molecule, composed of two chains which form a double stranded helix, each chain is made up of four chemical
building blocks called nucleotides. DNA carries the genetic instructions for all cellular processes (growth, development, function and reproduction).
Domain
A taxonomic category above the kingdom level. The three domains of life are Archaea, Bacteria and Eukarya.
Electron acceptor
An oxidizing agent that accepts electrons transferred from another compound.
Electron transport chain
A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP
Electrochemical gradient
The diffusion gradient of an ion / molecule
Endocytosis
Cellular uptake of biological molecules and particulate matter via formation of vesicles from the plasma membrane.
Endomembrane system
The collection of membranes inside and surrounding a eukaryotic cell that performs metabolic functions and regulates protein traffic. This system includes, the plasma membrane and membrane-enclosed organelles like; the
nuclear envelope, endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, and the central vacuole.
Endoplasmic
reticulum
An extensive membranous network in eukaryotic cells composed of ribosome-studded (rough) and ribosome-free (smooth) regions.
Endosymbiosis
A relationship between two species in which one organism lives inside the cell or cells of another organism
Endosymbiont theory
The theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells were engulfed by a host cell. The engulfed cell and its host cell
then evolved into a single organism
Enzymes
A macromolecule that serves as a catalyst in chemical reactions, increasing the reaction without being consumed.
Eukaryote
An organism with a membrane-enclosed nucleus and organelles. Typical size range 10-100 mm
Euchromatin
The less condensed form of eukaryotic chromatin that is available for transcription
Exocytosis
The cellular secretion of biological molecules by the fusion of vesicles containing them with the plasma membrane.
Extracellular matrix
ECM: The meshwork surrounding animal cells, consisting of glycoproteins, polysaccharides, and proteoglycans synthesised and secreted by cells.
Facilitated diffusion
The passage of molecules or ions down their electrochemical gradient across a biological membrane with the assistance of specific proteins, requiring no energy expenditure
Fermentation
A catabolic process that makes a limited amount of ATP from glucose (or other organic molecules) without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid.
Fungi
Eukaryotic organisms that have cell walls and obtain food from other organisms.
Gap junction
A type of intercellular junction in animal cells, consisting of proteins surrounding a pore that allows the passage of materials between cells