Unit 2 Cells

Cells

the basic structural functional units of every organism

Prokaryote

one of the types of cells - it domains bacteria and archaea, contain DNA in the nucleoid region, is generally smaller in size than the other type of cell eukaryotes and lacks internal membranes

Eukaryote

another type of cell - protists, fungi, and plants, its DNA is in the nucleus, contains membrane bound organelles which include internal membrane and its surface area to volume ratio is critical

Chromosomes

discrete units that DNA is organized into that carry genetic information

Organelles

membrane bound structure in eukaryotes

Nucleolus

nonmembranous structure involved in production of ribosomes; a nucleus has one or more nucleoli

Ribosomes

(small brown dots) complexes that make proteins; free in cytosol or bound to rough ER or nuclear envelope - they are comprised of ribosomal RNA and protein

Rough ER

contains ribosomes bound to the ER membrane to help compartmentalize the cell

Smooth ER

contains no ribosomes and synthesizes lipids, metabolizes carbohydrates and detoxifies the cell

Cisternae

flattened membranous sacs within the Golgi

Autophagy

lysosomes can recycle their own cell’s organic materials which allows the cell to renew itself

Lysosomes

membranous sac of hydrolytic enzymes that many eukaryotic cells use to digest (hydrolyze) macromolecules (in animal cells)

Peroxisomes

organelle with various specialized metabolic functions ; produces hydrogen peroxide as a by-product then it converts it to water

Golgi Apparatus

organelle active in synthesis, modification, sorting and secretion of cell products

Nucleus

made up of 3 parts: nuclear envelop, nucleolus, and chromatin- it contains most genes in the eukaryotic cell

Vacuoles

large vesicles derived from the endoplasmic reticulum and Golgi apparatus that are an integral part of a cell’s endomembrane system- also selective in transporting solutes so as a result the solution inside is different in composition than from the cytosol

Mitochondria

organelle where cellular respiration occurs and most ATP is generated

Chloroplast

Found in plants + algae are photosynthetic organelle that converts energy of sunlight to chemical energy stored in sugar molecules

Stroma

fluid around thylakoids which contains the chloroplast DNA and ribosomes as well as many enzymes

Microfilaments

two intertwined thin solid rods made of the protein actin that maintain cell shape (bear tension ) assist in muscle contraction and cell motility and division

Grana

stacks that membranous stacks can organize into

Thylakoids

flattened interconnected sacs that are membranous system inside the chloroplast

Intermediate Filaments

fibrous proteins made up varying subunits coiled into cables and are permanent structural elements of cells - maintain cell shape anchor nucleus and organelles and form the nuclear lamina that lines in the nuclear envelope

Microtubules

hollow, rod-like structures made of protein tubulin that grow from the centrosome

Actin

a globular protein

Cilia

microtubulle containing extensions that project some cells - back and forth motion - rapid power stroke moves cell in a direction perpendicular to the axis of the cilium

Flagella

microtubule containing extensions that project from some cells - undulates its snakelike motion driving a cell in the same direction as the axis of the flagellum

Plasma Membrane

functions as a selective barrier that allows passage of enough oxygen nutrients and wastes to service the entire cell

Krebs Cycle

AKA citric acid cycle occurs during one of the 3 metabolic stages during cellular respiration - the breakdown of glucose to carbon dioxide is completes (in prokaryotes takes place in the cytosol) - the carbon dioxide produced by respiration represents fragments of oxidized organic molecules

Electron Transport Chain

consisting of a number of molecules mostly proteins built into the inner membrane of the mitochondria of eukaryotic cells (the plasma membrane of respiring prokaryotes)

Calvin Cycle

second stage of photosynthesis that occurs in the stroma where plants algae and bacteria use energy (ATP & NADPH) from light dependent reactions to convert CO2 into sugars such as glucose providing food for the organism

Light Reactions

first stage of photosynthesis that converts solar energy into chemical energy (water +sunlight + chlorophyll —> ATP + NADPH - release oxygen)

Endosymbiotic Theory

an early eukaryotic cells engulfed a prokaryotic cell and the prokaryotic became an endosymbiont (cells that lives in another cell ) + become one functional organism (explains mitochondria and chloroplasts similarities)

Photosynthesis

chloroplasts in plants and other photosynthetic organisms capture light energy that is stored in sugar and other organic molecules

Amphipathic

membrane lipids that have both a hydrophilic + hydrophobic region (Ex: phospholipid)

Fluid Mosaic Model

a model to describe the structure of all membranes - referring to the fact the membrane is held together by weak hydrophobic interactions and can therefore move + shift and that membranes being comprised of many macromolecules

Integral Proteins

proteins that are embedded into the lipid bilayer (AKA transmembrane proteins )

Peripheral Proteins

proteins that are not embedded into the lipid bilayer (loosely bonded to the surface)

Glycolipids

carbohydrates bonded to proteins

Glycoproteins

carbohydrates bonded to proteins

Selective Permeability

the ability of membranes to regulate the substances that enter and exit

Polar

molecules with uneven charge distribution

Nonpolar

molecules with an even distribution of electrons lacking distinct positive and negative charges

Charged

transport of a molecule that does not require energy from the cell because of a solute is moving with its concentration or electrochemical gradient

Passive Transport

transport of e molecule that does not require energy from the cell because a solute is moving with its concentration or electrochemical gradient

Active Transport

transport of molecule that requires energy (ATP) because it moves a solute against its concentration gradient

Concentration Gradient

the process where molecules or particles more from an area of higher concentration to an area of lower concentration

Endocytosis

the uptake of molecules from vesicles fused from the plasma membrane (think opposite of exocytosis)

Diffusion

spontaneous process resulting from the constant motion of molecules ; substance move from a high to low concentration

Exocytosis

the secretion of molecules via vesicles that fuse to the plasma membrane (can fuse to the membrane by forming a bilayer)

Pinocytosis

nonspecific uptake of extracellular fluid containing dissolved molecules (takes in a protein coded vesicle)

Facilitated Diffusion

diffusion of molecules through the membrane via transport proteins

Carrier Proteins

undergo conformational changes for substances to pass

Channel Proteins

undergo conformational changes for substances to pass

Aquaporins

transmembrane proteins that facilitate the rapid selective transport of water and small solutes across cell membranes (specific channel protein for water)

Osmosis

the diffusion of water down this concentration gradient across a selectively permeable membrane

Tonicity

the ability of an extra cellular solution to cause a cell to gain or lose water

Hypertonic

cells immersed lose water to their extracellular surroundings

Isotonic

cells immersed have no net movement of water

Hypotonic

cells immersed gain water

Osmoregulation

cells must be able to regulate their solute concentration s and maintain water balance

Plasmolysis

vacuole shrinks and the plasma membrane pulls away from the cell wall

Turgid

a cell (most likely plant cells) that is swollen and firm due to being full of water