A2.2 SL / HL Flashcards
Cell theory
theory states thatall biological organisms are composed of cells; cells are the unit of life and all life come from preexisting life
Prokaryotes
any organism that lacks a distinct nucleus and other organellesdue to the absence of internal membranes
binary fission
the process of one cell simply dividing into two. It is most commonly used in archaea and bacteria, which are both prokaryotic organisms
Eukaryotes
any cell or organism that possesses a clearly defined nucleus. The eukaryotic cell has a nuclear membrane that surrounds the nucleus
mitosis
a process of cell duplication, or reproduction, during which one cell gives rise to two genetically identical daughter cells
meiosis
a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells
Inductive reasoning
a form of logical thinking that uses related observations to arrive at a general conclusion
spontaneous generation
the supposed production of livingorganismsfrom non-living matter, asinferredfrom the apparent appearance of life in somesupposedlysterileenvironments
Deductive reasoning
a form of logical thinking that uses a general principle or law to forecast specific results
Theory
a widely accepted explanation of a biological phenomenon based on sound evidence from rigorous empirical experiments and scientific observations
microscope
an instrument that is used to magnify small objects
Magnification
the increase in size of an object when it is viewed through a microscope or other optical device
Resolution
the ability to distinguish two objects from each other. Light microscopy has limits to both its resolution and its magnification
Field of view (FOV)
the maximum area visible through the lenses of a microscope, and it is represented by a diameter
Compound light microscope
a high magnification microscope that uses 2 lenses to compound (multiply) the level of magnification
Electron microscope
an instrument that uses a beam of electrons to magnify a specimen. It has a higher resolution power of up to 100,000X
Tunneling electron microscope (TEM)
a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image
Scanning electron microscope (SEM)
a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons
Freeze-fracture
physically breaking apart (fracturing) a frozen biological sample
Integral proteins
a type of membrane protein that is permanently attached to the biological membrane
fluid mosaic model
describes the main characteristics of the plasma membrane
Immunofluorescence
a method commonly used in neuroscience to detect viral antigens by directly applying fluorescent dyes to samples, such as nasopharyngeal aspirate or biopsy samples, and observing them under a fluorescent microscope
Fluorescent stains
a pivotal molecular technique that brings to light the structures within biological cells and tissues through fluorescence
antibodies
proteins that protect you when an unwanted substance enters your body
Cryogenic electron microscope
a version of electron microscopy that freezes many copies of a delicate sample into a glassy state and hits them with an electron beam
permeability
the passage of molecules through a biological membrane or a barrier
plasma membrane
amicroscopicmembrane oflipidsand proteins which forms the external boundary of thecytoplasmof a cell orenclosesavacuole, and regulates the passage of molecules in and out of the cytoplasm
Hydrophobic
a property of molecules that do not mix with water
cytoplasm
the gelatinous liquid that fills the inside of a cell. It is composed of water, salts, and various organic molecules
70s ribosomes
In prokaryotes, these subunits are50S(large) and30S(small). The total ribosome with both subunits is 70S in prokaryotes
80s ribosomes
found in the cytoplasm of eukaryotic cells
Capsule
a layer of slime outside the bacterial cell wall, composed mainly of polysaccharides or polypeptides
polysaccharides
long chains of carbohydrate molecules, composed of several smaller monosaccharides
Cell wall
a structural layer that surrounds some cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid
peptidoglycan
a polymer consisting of sugars and amino acids that forms a mesh-like peptidoglycan layer outside the plasma membrane of most bacteria, forming the cell wall
Phospholipid bilayer
a two-layered arrangement of phosphate and lipid molecules that form a cell membrane, the hydrophobic lipid ends facing inward and the hydrophilic phosphate ends facing outward
Pili
short, hair-like structures on the cell surface of prokaryotic cells
plasmids
a small, circular, double-stranded DNA moleculethat is distinct from a cell’s chromosomal DNA
Flagellum
hairlike structure that acts primarily as an organelle of locomotion in the cells of many living organisms
metabolic reactions
a chemical process in living systems that transforms molecules to make them more chemically stable, permeable, polar, and less toxic
Nucleoid
an irregularly shaped region within the prokaryotic cell that contains all or most of the genetic material
naked DNA
DNA that is not associated with lipids, proteins, or any other molecule to help protect it
conjugation
the process by which one bacterium transfers genetic material to another through direct contact
antibiotic resistance
occurs when bacteria evolve to evade the effect of antibiotics through multiple different mechanisms
membrane-bound organelles
a membrane bound structure found within a cell
compartmentalization
the separation of the cell interior in distinct compartments with specific local conditions that allow the simultaneous occurrence of diverse metabolic reactions and processes
nucleus
the structure in a cell that contains the chromosomes
nuclear envelope
the nuclear membrane, is made up oftwo lipid bilayer membranes that in eukaryotic cells surround the nucleus
Nuclear pores
a protein-lined channel in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm
euchromatin
the less tightly coiled DNA that allows transcription factors and chromatin remodelers access, enabling transcription to occur
heterochromatic
a cytologically dense material that is typically found at centromeres and telomeres
histones
a family of basic proteins that associate with DNA in the nucleus and help condense it into chromatin
nucleolus
spherical body within the nucleus of most eukaryotic cells, involved in the synthesis of ribosomal RNA (rRNA) and the formation of ribosomes
Smooth endoplasmic reticulum
tube-like structure located near the cell periphery. These tubules or tubes sometimes branch forming a network that is reticular in appearance. The network of smooth endoplasmic reticulum allows for an increased surface area to be devoted to storage of key enzymes
Rough endoplasmic reticulum
a cellular organelle composed of many folds of tissues and channels. It provides surface area for chemical reactions to take place. It is rough because its surface is covered with ribosomes. These ribosomes produce proteins
polypeptides
a continuous, unbranched chain of amino acids joined bypeptide bonds
Free ribosomes
unattached to any cellular structure and float freely around in the cytosol
golgi apparatus
a complex ofvesiclesand foldedmembraneswithin thecytoplasmof most eukaryotic cells, involved insecretionandintracellulartransport
vesicles
a structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer
exocytosis
a process for moving large molecules out of the cell to the cell exterior
Lysosomes
membrane-enclosed organelles that contain an array of enzymes capable of breaking down all types of biological polymers—proteins, nucleic acids, carbohydrates, and lipids
Transport vesicles
help move materials, such as proteins and other molecules, from one part of a cell to another
Secretory vesicles
a specialized cellular structure that carries proteins, peptides, or neurotransmitters for extracellular delivery in response to specific signals
cytoskeleton
a network of different protein fibers that provides many functions: it maintains or changes the shape of the cell
Microtubules
A narrow, hollow tube-like structure found in the cytoplasm(the fluid inside a cell) of plant and animal cells. Microtubules help support the shape of a cell
Actin filaments
the smallest component of the cytoskeleton, the internal protein skeleton of the cell
Intermediate filaments
fibrous cytoskeletal polymers intermediate in size between 6-nmactin filamentsand 23-nm microtubules that form the structural framework of nearly all eukaryotic cells
centrioles
a cylindrical organelle composed mainly of a protein called tubulin
spindle fibers
a network of filaments that are formed during the cell division process. They help in the movement of chromosomes during both mitosis and meiosis
centrosome
an organelle present in an animal cell that acts as the microtubule-organizing centre of the cell. It also regulates the cell cycle
basal bodies
a minute distinctively staining cell organelle found at the base of a flagellum or cilium and resembling acentriolein structure
Cilia
short eyelashlike filament that is numerous on tissue cells of most animalsand provides the means for locomotion of protozoans
Flagella
hairlike structure that acts primarily as an organelle of locomotionin the cells of many living organisms
mitochondria
a round to oval-shaped organelle found in the cells of almost all eukaryotic organisms. It produces energy, known as ATP, for the cell
cellular respiration
the process by which organisms combine oxygen with foodstuff molecules
ATP (adenosine triphosphate)
the source of energy for use and storage at the cellular level
protists
any member of a group of diverse eukaryotic, predominantly unicellular microscopic organisms
cell wall
structural layer that surrounds some cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid
osmotic stress
physiologic dysfunction caused by a sudden change in the solute concentration around a cell, which causes a rapid change in the movement of water across its cell membrane
cellulose fibers
a polymer made of repeating glucose molecules attached end to end
turgor pressure
the force within the cell that pushes the plasma membrane against the cell wall
large central vacuole
large, membrane-bound organelles found in plant cells that act as a storage space for water and other molecules in the cell
chloroplast
an organelle within the cells of plants and certain algae that is the site of photosynthesis
photosynthesis
the process by which green plants and certain other organisms transform light energy into chemical energy
chlorophyll
a pigment present in all green plants and a few other organisms. It is required for photosynthesis, which is the process by which light energy is converted into chemical energy
Metabolism
the chemical reactions in the body’s cells that change food into energy
Catabolic reactions
break down larger molecules, such as carbohydrates, lipids, and proteins from ingested food, into their constituent smaller parts
Anabolic reactions
reactions that build smaller molecules into larger molecules
sensitivity
the ability of an organism or organ to respond to external stimuli
receptor proteins
proteins molecules located on the cell surface or within the cytoplasm that function by specifically recognizing and binding to a ligand molecule
homeostasis
any self-regulating process by which biological systems tend to maintain stabilitywhile adjusting to conditions that are optimal for survival
Conformers
Any organism whose internal environment is highly influenced by external factors
Regulators
Any organism whose internal environment is highly influenced by internal factors
Sessile
an organism that is anchored to a substrate and cannot move about freely
Motile
an organism has the capability to move under its own power
cell division
the division of a cell into two daughter cells with the same genetic material.
specialization
cells that have a distinctive structures and provide unique functions in the body
Asexual reproduction
amode of reproductionin which a new offspring is produced by a single parent
clones
cell or organism that is genetically identical to the original cellor organism from which it is derived
Sexual reproduction
the production of new organisms by the combination of genetic information of two individuals of different sexes. In most species the genetic information is carried on chromosomes in the nucleus of reproductive cells called gametes, which then fuse to form a diploid zygote
gametes
a reproductive cell of an animal or plant
variation
any difference between cells, individual organisms, or groups of organismsof any species caused either by genetic differences
Excretion
the process of removing wastes and excess water from the body
Nutrition
the process of taking in food and converting it into energy and other vital nutrients required for life
Domains
the highesttaxonomic rankof all organisms taken together
Eubacteria
prokaryotic microorganismsconsisting of a single cell lacking a nucleus and containing DNA is a single circular chromosome
Archaea
single-celled microorganisms with structure similar to bacteria
Eukarya
any cell or organism that possesses a clearly defined nucleus. The eukaryotic cell has a nuclear membrane that surrounds the nucleus
heterotrophs
an organism that eats other plants or animals for energy and nutrients
autotrophs
an organism that can produce its own food using light, water, carbon dioxide, or other chemicals
Saprotrophs
organism that feeds on nonliving organic matter known as detritus at a microscopic level
decomposers
An organism, often a bacterium, fungus, or invertebrate that feeds on and breaks down dead plant or animal matter, making organic nutrients available to the ecosystem
Erythrocytes
A type of blood cell that is made in the bone marrow and found in the blood. Erythrocytes contain a protein called hemoglobin, which carries oxygen
Haemoglobin
A protein inside red blood cells that carries oxygen from the lungs to tissues and organs in the body and carries carbon dioxide back to the lungs
muscle cells
the smallest subunit of all muscular tissues and organs throughout the body
multinucleated
eukaryotic cells that have more than one nucleus
Hyphae
The long filamentous branching in fungus and actinobacteria
mycelium
a network of fungal threads orhyphae
Aseptate hyphae
characterized by the absence of a cross wall, or septa. These hyphae contain many nuclei
phloem
plant vascular tissue that conducts foods made in the leaves during photosynthesis to all other parts of the plant
vascular plants
those varieties of plants that have special vascular tissue in them. The two types of vascular tissue,phloem, and xylem are behind the movement of water, minerals, and the products of photosynthesis
Sieve tube elements
thin-walled cells that are alive at maturity, although the protoplast is greatly changed, and they generally lack nuclei
companion cells
A type of cell found within thephloemof flowering plants. Each companion cellis usually closely associated with asieve element
gram positive
bacteria classified by the color they turn in the staining method
gram negative
bacteria have an outer membrane. However, they have a thinner peptidoglycan cell wall. This means they do not hold the blue dye used in Gram testing and do not appear blue. Instead, they appear red or pink in color
microvilli
finger-shaped plasma membrane protrusions that are found at the surface of a large variety of cell types but are most numerous and elaborated on simple epithelial
