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79 Cards in this Set
- Front
- Back
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purmidines
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-in nucleic acid
-single rings: cytosine (C), thymine (T), Uracil (U) |
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Purines
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-in nucleic acid
-double rings: Adenine (A), Guanine (G) |
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peptides
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-short, 20 or fewer amino acids (some hormones and signaling molecules)
-oligopeptides |
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proteins
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-polypeptide
-monomers are amino acids linked to form peptide bonds(by covalent) -amino and carboxylic acid functional group -R group differs in each amino acid H3 N+ - C - COO- |
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nucleotide
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-pentose sugar + N base + phosphate group
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nucleoside
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- pentose sugar + N base
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protein primary structure
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-sequence of amino acids by single peptide bond
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protein secondary structure
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-regular, repeated spatial patterns in different regions, resulting from hydrogen bonding
-alpha helix= right handed coil -beta pleated sheet= 2 or more polypeptide chains are extended and aligned |
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protein tertiary structure
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-polypeptide chain is bent and folded; results in definitive 3-d shape
-outer surfaces present functional groups that can interact with other molecules |
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protein quaternary structure
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-2 or more polypeptide chains bound together by hydrophobic and ionic interactions, and hydrogen bonds
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metabolic pathways
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-product of 1 reaction is a substrate for the next, series of reactions
-first reaction is the commitment step- other reactions then happen in sequence -feedback inhibition the final product acts as a noncompetitive inhibitor or the first enzyme, which shuts down the pathway |
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protein denaturation
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-alterations in pH, salt concentration, temperature, or other environmental factors can cause protein to unravel
-loss of protein's native structure -biologically inactive |
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enzymes
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-organic catalysts are substances that speed up reactions
-all enzymes are proteins but not all proteins are enyzmes -bind to specific substrate by active site -reactants are substrates that bind to specific site on enzyme-the active site |
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cofactors
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-inorganic ions
ie. metal ions |
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coenzymes
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-add or remove chemical group from the substate
-organic -ie. vitamins |
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prosthetic groups
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-(non amino acid groups) permanently bound to their enzymes
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irreversible inhibition
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-regulation of metabolism
-inhibitor covalently binds to side chain in active site -enzyme is permanently inactivated |
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reversible inhibition
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-regulation of metabolism
-competitve inhibitor competes with natural substrate for active site -aggressive -noncompetitive inhibitor binds at site distinct for the active site causing change in enzyme shape and function |
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allosteric regulation
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-regulation of metabolism
-non substrate molecule binds to a site other than active site -enzyme changes shape, which alters chemical attraction of the active site for substrate -can activate or inactivate enzymes |
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dna
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-sugar= deoxyribose
-bases= adenine, cytosine, guanine, thymine -double strand helix -informational molecule: genetic information in sequence of base pairs |
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rna
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-sugar=ribose
-bases= adenine, cytosine, guanine, uracil -single strand |
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homeostasis
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-maintenance of stable internal conditions
-balance |
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amino acid base pairing
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-adenine and thymine (A-T)
-cytosine and guanine (C-G) |
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2 functions of dna
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1.replication
2.gene expression-base sequences are copied to RNA, and specify amino acids in sequences in proteins -dna (brain) -> transcription -> RNA -> translation -> polypeptide (protein goes to wherever needed) |
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genome
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-complete set of dna in living organisms
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genes
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-dna sequences that encode specific proteins and are transcribed into rna
-not all genes are transcribed in all cells of an organisms -part of chromosomes |
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gene
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-sequence of dna that resides at a particular site on a chromosome, called a locus (many locus= loci)
-karyotype: 46 chromosomes xy |
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cell theory
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-first unifying theory of biology
-cells: fundamentals units of life -all organisms are composed of cells coming from preexisting cells |
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cell volume
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-determines its metabolic activity relative to time
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cell surface area
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-determines the number of substances that can enter or leave the cell
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2 types of microscopes visualize small cells
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-light microscope 0.2 micrometers
-electron microscopes 2.0 nanometers |
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plasma membrane
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-selective permeable membrane barrier that allows cells to maintain a constant internal environment
-important in communication and receiving signals -has proteins for biding and adhering to adjacent cells -cells->create tissue->organs |
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prokaryotes
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-without membrane enclosed compartments
-no organelles -no nucleus -enclosed plasma membrane made of phospholipids -dna located in nucleoid -cytoplasm -cell wall -capsule flagellus -smaller than eukaryotic cells |
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eukaryotes
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-have membrane-enclosed compartments called organelles, such as nucleus (dna contained)
-cytoplasm and ribosomes -each organelle plays a specific role in cell functioning -cytoplasm -ribosomes -cytosol -organelles-chloroplasts -cell wall (plants) -capsule |
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cytoplasm
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-consist cytosol (water and dissolved material and suspended particles)
-consist of ribosomes (sites of protein synthesis) |
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peptidoglycans
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-in prokaryotic cells bacteria cell walls
-some rod like shape bacteria have a network of actin-like protein structures to help maintain their shape |
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capsule
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-in prokaryotic cell
-bacteria have slimy layer in polysaccharide |
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flagella
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-how prokaryotes swim
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ribosomes
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-site of protein synthesis
-occur in both prokaryotic and eurakryotic cell and have similar structure-one larger and one smaller subunit -each subunit consists of ribosomal rna (rRNA) bound to smaller protein molecules |
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ribosomes - not membrane-bound organelles
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-in eukaryotes: free in cytoplasm, attached to endoplasmic reticulum, or inside mitochondria and chloroplasts
-in prokaryotic cells, ribosomes floar freely in cytoplasm |
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nucleus
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-in eukaryotic cell
-largest organelle -location of dna and dna replication -site where dna is transcribed to rna then produce proteins -surrounded by 2 membranes that for nuclear envelope for protection -nuclear pores in envelope control movement of molecules between nucleus and cytoplasm -dna combines with proteins to form chromatin in long, thin threads called chromosomes -contains nucleolus, where ribosomes begin to assemble from RNA and proteins |
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endomembrane system
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-in eukaryotic cell
-include nuclear envelope -endoplasmic reticulum -golgi appartus -lysosomes -tiny membrane surrounded vesicles shuttle substances between the various compartments as well as to plasma membrane |
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endoplasmic reticulum
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-network of interconnected membranes in cytoplasm with large surface area
- 2 distinct regions 1. smooth ER- lack ribosomes 2. rough ER- has ribosomes studding its surface |
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smooth er
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-synthesizes lipids and steroids for hormonal reproduction
-metabolizes carbohydrates for energy -detoxifies poisons -stores calcium for electronegativity exchange -glycogen degradation site for energy in liver and muscles |
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rough er
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-has bound ribosomes with secrete glycoproteins (-proteins and cho's)
-distributes transport vesicles, proteins surrounded by membranes -membrane factory for the cell |
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golgi apparatus
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-consists of flattened membranous sacs called cristernae
-shipping and receiving center |
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fuctions of golgi appartus
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-modifies products of er
-manufactures certain macromolecules (polysaccharides in plants) for energy and structure -sorts and packages materials into transport vesicles |
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lysosomes
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-primary lysosomes originate from golgi apparatus
-contain digestive enzymes and are the site where macromolecules are hydrolyzed into monomers for energy -carry waste out |
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mitrochondria
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-in eukaryotes, molecules are first broken down in cytosol
-partially digested molecules enter mitochondria, here chemical energy is converted to energy rich ATP -cells that require a lot of energy often has more mitochondria ie. heart -2 membranes: outer-porous and inner-extensive folds called cristae to increase surface area for energy production -fluid filled matrix inside the inner membrane contains enzymes, dna and ribosmes |
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plastids
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-plant and algae cells contain plastids that can differentiate into organelles- some are used for storage
-chloroplasts contain chlorophyll and is site of photosynthesis -photosynthesis converts light energy into chemical energy |
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other organelles in eukaryotes
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-specialized functions
-peroxisomes collect and break down toxic by-products of metabolism, such as H2O2, using specialized enzymes -scavengers of bad stuff -gloxysomes found only in plants are where lipids are converted to carbohydrates for growth |
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vacuoles
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-in eukaryotic cells
-in plants and fungi |
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function of vacuole
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1. storage of waste products and toxic compounds; some may deter herbivores
2.structure for plant cells-water enters vacuole by osmosis, creating turgor pressure 3. reproduction: vacuoles in flowers and fruits contain pigments whose colors attract pollinators and aid seed dispersal 4. catabolism-digestive enzymes in seeds' vacuoles hydrolyze stored food for early growth |
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functions of cytoskeleton
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-supports and maintains cell shape
-holds organelles in position -moves organelles -involved in cytoplasmic streaming -interacts with extracellular structures to anchor cell in place |
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3 components of cytoskeleton
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-microfilaments
-intermediate -microtubules |
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microfilaments
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-in cytoskeleton
-help cell or parts of cell to move -determine cell shape -made from actin-protein -filaments can be made shorter or longer |
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intermediate filaments
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-in cytoskeleton
-50 different kind -have tough ropelike protein assemblages, more permanent than other filaments and do not show dynamic instability -anchor cell structures in place -resist tension, maintain rigidity -stronger than micromolecules than microfilaments -make tissue |
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microtubules
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-in cytoskeleton
-largest diameter components, -2 roles: 1. form rigid internal skeleton for some cells or regions 2. act as a framework for motor proteins to move structures in cell -pathways for substances to move-road structure of cell -line moveable cell appendages -cilia- short, usually many present, move with stiff power stroke and flexible recovery stroke -flagella- longer usually one or two present, movement is snakelike |
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extracellular structures
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-allow cells to communicate with external environment
-secreted to outside of plasma membrane -interacting -in eukaryotes, these structures have 2 components: 1.prominent fibrous macromolecule 2. gel-like medium with fibers embedded -plant cell wall-semi rigid structure outside the plasma membrane (steady shape) -fibrous components is the cellulose (cho's, polysaccharides, glucose) -gel like matrix contains cross linked polysaccharides and proteins |
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3 major functions of cell wall
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-provides support for the cell and limits volume by remaining rigid
-acts as barrier to infection (protection) -contributes to form during growth and development |
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extracellular matrices
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-in animal cells
-holds cells together in tissues -contribute to physical properties of cartilage, skin, and other tissues -filter materials -orient cell movement during growth and repair |
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cell junctions
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-specialized structures that protude form adjacent cells and glue them together
- 3 structures: tight junctions, desmosomes, and gap junctions |
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biological membrane
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-general structure of membranes is known as fluid mosaic model
-phospholipids form bilayer which is like a lake in which variety of proteins float -2 regions: hydrophillic regions- electrically charged heads that associate with water molecules hydrophobic regions-nonpolar fatty acid tails that do not dissolve in water -may differ in lipid composition as there are many types of phospholipids -differ in fatty acid chain length, degree of saturation, kinds of polar groups present |
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2 important factors in biological membrane fluidity:
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-lipid composition-types of fatty acids can increase or decrease fluidity
-temperature-membrane fluidity decreases in colder conditions |
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biological membranes contains proteins
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-peripheral membrane proteins lack hydrophobic groups and are not embedded in bilayer
-integral membrane proteins are partly embedded in bilayer -anchored membrane protein- have lipid components that anchor them in bilayer -transmembrane protein- extend through the bilayer on both sides |
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plasma biological membranes
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-carbohydrates located on outher membrane serve as recognition sites
-glycolipid- carbohydrate bonded to lipid -glycoprotein- carbohydrate bonded to protein |
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selective permeability
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-biological membrane allow some substances, and not others, to pass.
-passive transport does not require energy -active transport- requires energy |
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passive transport
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No atp required. 2 types of diffusion
-simple diffusion -facilitated diffusion through channel proteins or aided by carrier proteins |
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speed of diffusion depends on
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-diameter of molecules- smaller molecules diffuse faster
-temperature of the solution-higher temperatures lead to faster diffusion -concentration gradient the greater the concentration, the faster a substance will diffuse -for equilibrium isotonic solution in animal cell |
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diffusion
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-higher concentration inside the cell causes the solute to diffuse out, and a higher concentration outside causes solute to diffuse in, for many molecules
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osmosis
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-diffusion of water across membranes
-depends on concentration of solute molecules on either side of membrane -water passes through special membrane channels -if not specific cell will fill and burst |
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when comparing 2 solutions separated by a membrane
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-hypertonic solution has higher solute concentration on outside (lysed or turgid normal in plants
-isotonic solutions have equal solute concentrations on outside (normal in animal or flacid) -hypotonic solution has lower solute concentration (shriveled or plasmolyzed) |
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channel proteins
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-aids diffusion
-intergral membrane that form channels across the membrane -substances can also bind to carrier proteins to speed up diffusion -no atp |
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aquaporins
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-water crosses membranes through specific channels
-no atp -allow large amount of water to move against its concentration gradient -may hitchhike with ions such as NA+ as they pass through channels |
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active transport
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-requries energy to move substances against their concentration gradient
-energy source ATP -substances move in direction of cell's needs, usually by means of specific carrier protein |
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2 types of active transport
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1. primary active transport involves hydrolysis of ATP for energy
2. secondary active transport uses energy from ion concentration gradient, or an electrical gradient |
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sodium-potassium (Na+ -K+) pump
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-active transport
-an intergral membrane protein that pumps Na+ out of cell and K+ in -one molecule of ATP moves 2 K+ and 3 Na+ ions -remember illustration |
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endocytosis 3 types
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-moves material in cell through vesicle
1.phagocytosis- cellular eating 2. pinocytosis- cellular drinking 3. receptor-mediated endocytosis |
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exocytosis
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-moves materials out of cell in vesicles
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