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Criado por Makenna Ornes
quase 3 anos atrás
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Questão | Responda |
cell theory | 1) 1 or more cells 2) smallest unit of living things 3) all cells come from preexisting cells |
3 things in common for all cells | 1) plasma membrane 2) DNA 3) cytoplasm |
prokaryotic cell & example | -single-celled -no nucleus -no membrane-bound organelles -have DNA (not enclosed in a nucleus) -ex: bacteria |
eukaryotic cell & examples | -has a "true nucleus" that contains DNA -membrane-bound organelles -unicellular or multicellular |
in body, what % are human or bacterial cells/ | 10% body cells are human 90% body cells are bacterial |
why does surface to volume ratio matter? | responsible for small size of cells but maximizes interaction surfaces -as linear dimensions (3D object) increase, volume increases faster than surface area does |
what are not considered organelles? | ribosomes & centrioles |
chemical reactions take place in... | organelles |
microscopy | use of microscopes to view objects |
micrograph | photograph of image formed by microscope |
compound light microscope | 2 or more glass lends that bend light rays to form enlarged image -cells are often dyed -only provides sharp images when mag is 2000x or less |
electron micoscope | uses magnetic lends to bend beams of electrons -reveals smaller details than light microscopes; great depth |
receptor proteins | docks for signaling molecules like hormones; triggers changes in cell activities |
recognition proteins | sit on surface of cell; chemical fingerprints that identify cell as certain type |
transport proteins | allow specific substances to move across membrane |
selective permeability | allows some substances in but not some others -controls when & how much crossing -small, nonpolar substances are permeable -ions or large, polar molecules cross through transport proteins or pumps |
lipids/proteins can have sugars attached to external surface which are | glycoproteins & glycolipids |
key functions of the nucleus | 1) prevents DNA from getting tangled up with structures in cytoplasm - protects it 2) outer membranes of nucleus are boundary where movement of substances to & from cytoplasm can be controlled |
nuclear envelope | -double-membrane system -surrounds fluid part of nucleus (nucleoplasm) & proteins embedded in layers -threadlike proteins attach to inner surface & anchor DNA molecules to envelope & keep them organized |
masses in nucleus are called... what do they do? | nucleolus -construction site where proteins & RNA are combined to make parts of ribosomes |
chromatin | cell's DNA & all proteins associated with it |
chromosomes | double-stranded DNA molecule that carries genetic information |
endomembrane system | system in cells that includes ER, golgi apparatus, & vesicles; in which new proteins are modified into final form & lipids are assembled |
endoplasmic reticulum | flattened channel that starts at nuclear enveloped & goes through cytoplasm -lipids assembled in smooth er -rough er modifies new polypeptide chains -"raw" polypeptide chains are processed into final proteins |
ribosome | platform for building a cell's proteins -parts synthesized in nucleolus |
rough er | -strudded with ribosomes -modifies new polypeptide chains |
smooth er | -no ribosomes; flat connecting pipes -lipids are assembled |
golgi body/apparatus | -series of flattened sacs -enzymes on sacs finish proteins/lipids, then package in vesicles for shipment to specific locations |
vesicle | tiny sac that moves through the cytoplasm or takes up positions in it |
lysosome | type of vesicle that breaks down/chemically digests substances -can digest whole cell or just cell parts -often fuse with other vesicles that formed at plasma membrane & contain bacteria |
peroxisomes | sacs of enzymes that brask down fatty acids & amino acids -creates hydrogen peroxide which is converted to water & oxygen |
mitochondria | -makes ATP in inner compartment -double-membrane system -requires oxygen -has own DNA: mtDNA & has some ribosomes -in outer compartment, enzymes |
the inner membrane of mitochondria is called... | cristae |
cytoskeleton | system of interconnected fibers, threads, & lattices in cytosol |
microtubules | largest cytoskeleton elements; spatially organize interior of cell & help move cell parts -long tiny tubules made of tubulin protein chromosone movement during cell division tracks for organelle movement |
microfilaments | -reinforce part of cell; anchor some membrane proteins -long filaments constructed of actin protein subunits -responsible for cellular locomotion & muscle contraction -establish basic shape/strength of cell |
intermediate filaments | -strong cables of protein subunits -type depends on intermediate -adds strength; anchors filaments of 2 proteins (actin & myosin) when they interact in muscle cells; enables muscles to contract |
flagella | tail-like motile structures in eukaryotic cells -arise from centrioles |
cilia | short, hair-like projections in eukaryotic cells -arise from centrioles |
concentration | # of molecules of a substance in a certain amount of fluid |
gradient | # of molecules in one region is not same as in another |
diffusion | net movement of like molecules/ions down a concentration gradient -high to low |
passive transport | diffusion of solute through channel/carrier protein without use of energy |
ventilation | movement of gases (not passive) |
respiration | exchange of gases (passive) |
osmosis | diffusion of water across selectively permeable membrane in response to solute concentration gradients |
water ALWAYS moves from... | hypotonic to hypertonic |
tonicity | concentration of solutes in a solution |
isotonic | solute concentrations same on either side of cell membrane -no net flow of water |
hypotonic | fewer solutes in solution, higher solute concentration inside cell; water will move into cell & will cause cell to swell & burst AKA HEMOLYSIS |
hypertonic | more solutes in solution, lower solute concentration inside cell; water will move out of cell & will cause cell to shrink & shrivel AKA CRENATION |
transporter proteins | -span lipid bilayer -help solutes cross membrane -specific to solute -provide a channel for ions/molecules down concentration gradients -doesn't require ATP energy |
active transport | -requires energy -membrane pumps = move substances against their concentration gradient -ATP provides most energy for this type |
endocytosis | -active transport; vesicle transport -"coming inside cell"; cell takes in substances next to its surface -small indentation forms, balloons inward, pinches off -phagocytosis = when it brings in organic matter "cell eating" |
exocytosis | -active transport; vesicle transport -"moving out of cell"; vesicle moves to surface & protein-studded lipid bilayer of its membrane fuses with plasma membrane -contents released to outside |
chemical reactions either _____ or _____ energy | release or require energy |
anabolism | put together small molecules |
catabolism | breaks down large molecules |
metabolism def | chemical reactions in cells |
where is energy store in ATP? | stored energy is contained in bond between 2nd & 3rd phosphate groups |
ATP supply must be renewed so... | phosphate/phosphate group (has already been split off) is attached to ADP (adenosine diphosphate) |
ATP/ADP cycle | -mechanism of ATP renewal; when ATP donates a phosphate group to other molecules, reverts to ADP, & forms again by phosphorylation of ADP |
reactant | any substance that is part of a metabolic reaction |
intermediate | substance that forms between beginning & end of metabolic pathway |
products | substances present at end of reaction/pathway |
most enzymes are proteins but ALL are... | catalysts |
substrate | reactant/precursor for reaction; specific molecule(s) that an enzyme can chemically recognize, briefly bind to, & modify in specific way |
active site | crevice on surface of enzyme where substrate is present & a specific reaction is catalyzed |
homeostasis pH range of enzymes | 7.35 to 7.4 |
many coenzymes are derived from... | vitamins |
controls can... | 1) boost action of enzymes 2) slow it down 3) adjust how fast new enzyme molecules are made |
cellular respiration | process by which cells break apart carbohydrates, lipids, proteins to form ATP -glucose is common raw material -mostly aerobic |
step 1: glycolysis | -process by which glucose is partially broken down to pyruvate with net yield of 2 ATP -substrate: glucose -intermediate: PGAL -products: 2 pyruvate, 2 NADH, 2 net ATP -occurs in cytoplasm; ANAROBIC |
pyruvate | 3 carbons |
phosphorylation | attachment of unbound phosphate to a molecule -adds energy to glucose to begin steps of glycolysis |
step 2: Krebs cycle aka citric acid cycle | -stage of AEROBIC respiration in which pyruvate is completely broken down to carbon dioxide & water & 2 ATP form -substrate: 2 pyruvate -intermediate: acetyl-CoA -products: 2 ATP, 6 CO2, 8 NADH, 2 FADH2 -NADH & FADH2 are electron carriers -occurs in mitochondria |
step 3: electron transport chain/system | -AEROBIC; occurs in mitochondria -NADH & FADH2 carry electrons to this step -H+ flows across membranes & flow drives ATP formation -substrate: NADH/FADH2, oxygen -intermediate: hydrogen concentration ish -products: 32 ATP, H2O -H+ concentration gradient is formed |
total net yield of cellular respiration | 36 ATP |
lactate fermentation | -process coverts pyruvate from glycolysis to lactic acid; makes ADP -ANAROBIC; produces ATP quickly but not for long -occurs during sudden, strenuous exercise -excess glucose is stored as glycogen |
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