Unit 2 Exam Flashcards
Cell theory
- All organisms are composed of 1 or more cells
- Cells are the smallest unit of life
- New cells arise only by division of pre existing cells
Nuclear envelope
Protective phospholipid bilayer with pores allowing certain molecules to exit/enter
Cytoskeleton
Supports organelles and cell shape and plays a role in cell motion; microtubule, intermediate filament, actin filament
Microtubule
Tube of protein molecules
Intermediate filament
Intertwined Protein fibers that provide support and strength
Actin filament
Twisted protein fibers that are responsible for cell movement
Centriole
Complex assembly of microtubules that occurs in pairs
Cytoplasm
Semifluid matrix that contains the nucleus and other organelles
dehydration reaction
removal of OH- and H+ to form a covalent bond between monomers
hydrolysis reaction
hydrogen atom is attached to one subunit and and a hydroxyl group to the other, breaking a specific covalent bond in a macromolecule
isomers
organic molecules with the same molecular or empirical formula but different arrangement of atoms
structural isomers
differ in the actual carbon skeleton; ex. glucose and fructose
stereoisomers
differ in the spatial arrangement of groups attached to carbon skeleton; ex. glucose and galactose
chiral molecules
when 4 groups attached to carbon atom are different
enantiomers
mirror image isomers
polymers
constructed by joining together many small similar chemical subunits called monomers (carbohydrates, protein, and nucleic acids)
hydroxyl group
on all 4 macromolecules
carboxyl group
proteins and lipids
amino group
proteins and nucleic acids
methyl group
proteins and nucleic acids
functions of proteins (7)
enzymes (catalysts), structural support, defense (snake venom), transport (hormones like insulin), movement, regulation, and storage
nucleic acids
DNA/RNA, polymers of smaller molecules called nucleotides, made of sugar, nitrogenous base, and phosphate group
nucleotides in DNA
adenine (A), thymine (T), guanine (G), and cytosine (C)
base pairing in DNA
A pairs with T
G pairs with C
nucleotides in RNA
adenine (A), guanine (G), cytosine (C), and uracil (U)
base pairing in RNA
A pairs with U
G pairs with C
DNA vs RNA reactivity
DNA has deoxyribose sugar, has one less oxygen containing hydroxyl group, making it more stable than RNA, which has ribose sugar
DNA function
encodes genetic information and keeps it safe for reproduction
RNA function
reads the DNA code and uses it to build proteins, then moves it to ribosomal protein factories
bonds holding nucleic acids together
phosphodiester bonds
saturated
holds the max number of hydrogens per carbon
unsaturated
contains carbon-carbon double bonds, preventing them from binding to the max number of hydrogens
nucleolus
dense body of RNA and protein within nucleus, makes ribosomes
chromatin
consists of loosely coiled fibers of DNA and protein, condenses to form chromosome
ribosomes
located in prokaryotic and eukaryotic cells, made up of protein and RNA
monosaccharides
simple 6 carbon sugar molecules; glucose, fructose, and galactose
disaccharides
2 monosaccharides bonded together; lactose (glucose and galactose), maltose (glucose and glucose), sucrose (glucose and fructose)
polysaccharides
multiple monosaccharides
glycogen
polysaccharide made of glucose units, used for energy storage in animals
starch
polysaccharide used for energy storage in plants
cellulose
polysaccharide used in plants for structural support
amino acid
monomer of protein, contain an amino group and an acidic carboxylic acid group
peptide bond
covalent bond that links 2 amino acids together
primary structure of a protein
amino acid sequence
secondary structure of a protein
hydrogen bonding patterns
tertiary structure of a protein
final folding into shape of a globular protein
quaternary structure of a protein
arrangement of subunits, when 2 or more polypeptide chains associate to form a protein
triglyceride
one glycerol molecule attached to 3 fatty acids
glycerol
each carbon bears a hydroxyl group, forms the backbone of a lipid molecule
phospholipid
glycerol, fatty acids, and a phosphate group
endoplasmic reticulum
network of interconnected membranes
rough ER
synthesizes proteins, rough with ribosomes
smooth ER
synthesizes lipids and hormones, contain significantly less ribosomes, contain many embedded enzymes
golgi apparatus
“packaging,” (post office for the cell), receives proteins from rough ER to pack up and ship out, consists of flattened sacs connected to ER, uses transport vesicle made up of phospholipids
lysosomes
“cleanup crew,” tiny membrane sacs containing enzymes to break down carbohydrates, proteins, and nucleic acids, absorbs problems to break it down safely
peroxisome
type of microbody with several oxidase enzymes that attack organic substances and degrade toxins, hydrogen peroxide is a byproduct and toxic to cells, so it pumps out catalase, an enzyme to clean it up
mitochondria
elongated fluid-filled sacs free in cytosol, produce key enzymes for metabolism and produces large amounts of ATP
microbody
enzyme-bearing vesicles in eukaryotic cells
proteasomes
large, cylindrical complexes that cells use to recycle their proteins
vacuoles
specialized membrane bound structures in plant cells
cristae
inner, folded membrane in mitochondria
chloroplasts
use light to generate ATP in plant cells
endosymbiosis
proposes that some of today’s eukaryotic organelles evolved as a consequence of symbiosis arising between two cells that were originally thought to be free living; ex. mitochondria might have originated as bacteria
chlorophyll
photopigment, makes plants green, can absorb light energy
nucleoid
in prokaryotes that hold DNA, not within a membrane
ribosomes
large, macromolecular machines composed of RNA and proteins, that synthesize all cellular proteins
ribosomal RNA
combination of RNA
messenger RNA
mRNA, carries coding information from DNA
transfer RNA
tRNA, carries amino acids
endocytosis
moves material in cell
phagocytosis
cell taking in solid particles of food
pinocytosis
cell taking in fluids
exocytosis
exporting material out of cell, likely through secretory vesicle
cytoskeleton
dynamic system that support the shape of the cell and anchor organelle to specific locations; actin filament, intermediate filament, and microtubules
actin filament
microfilaments, made up of globular protein actin, tiny rods arranged in meshwork or bundles that aid in cellular movement
microtubules
largest, long slender tubes that form a cellular skeleton to help maintain cell shape, made up of alpha and beta tubulin
intermediate filament
most durable and versatile, tough fibrous, provide more structural stability; ex. keratin
centrosome
nonmembranous structure near the golgi apparatus, houses centrioles, microtubules organizing center
centrioles
barrel shaped organelles that are important for cell division
motility
ability of a cell to move
taxis
directed movement, movement with a purpose
flagella
rod like extensions of a cell used for movement
flagella in prokaryotic cells
rotate on proton pump, accelerating the cell forward, made up of microtubules, small and narrower
flagella in eukaryotic cells
use ATP to move, run in a bending movement, consists of tubulin proteins, large and thick
cilia
many hair like extensions used to move the cell or items over the cell; ex. food in trachea is moved out by cilia
cell wall in bacteria
peptidoglycan
cell wall in plants
made of cellulose
glycolipids
lipids with carbohydrate heads
collagen fibers
made of collagen fibers with higher tensile strength
elastin fibers
generally lower tensile strength but higher elasticity
fibronectin
glycoprotein, shorter fibers that connect to other fibers
extracellular matrix in animal cells
collagen fibers, elastin fibers, and fibronectin fibers
MHC proteins
self from non self recognition
glycoprotein
protein with carbohydrate attached to polypeptide
adherin junctions
use the protein cadherin (glycoprotein) to link cells by “zippering,” link cells together and connect to actin filament, underneath septate/tight junctions
desmosomes
unique to vertebrates, cadherin based junction, usually circular or spot like
septate junctions
found in invertebrates, ladder like structure of protein to seal off a sheet of cells or block passage of material between cells
gap junctions
in animal cells, specialized protein channels that directly connect the cytoplasm of neighboring cells; cell to cell communication; typically the bottom junction
plasmodesmata
cytoplasmic bridges that connect plant cells, allowing molecules to travel between them, through cell walls
tight junctions
found in vertebrates, belt-like attachment around cells, creating a permeability barrier, separating tissue spaces and regulating movement
4 components of cell membranes
phospholipid bilayer, integral membrane proteins, peripheral membrane proteins, cell-surface markers
functions of plasma membrane proteins
transporters, enzymes, cell-surface receptors, cell surface identity markers, cell to cell adhesion, cytoskeleton anchor
transmembrane domain
integral membrane proteins reach from inside to outside of cell, alpha helixes
pore protein
transmembrane protein porin creates large open tunnels (pores) in a membrane with beta-pleated sheets
diffusion
net movement of substances from areas of high concentration to low concentration; ex. oxygen and steroid molecules are nonpolar so they easily pass through the membrane if concentration gradient permits
simple diffusion
diffusion that requires no energy, based on unequal concentrations, substances can pass between the phopholipids
facilitated diffusion
passive diffusion, requiring no energy, but done through specialized membrane channels, required for polar molecules
ion channels
hydrophilic interior that provides an aqueous channel for ions to pass through when open
carrier proteins
bind specifically to the molecule they assist to go in/out of cell
hypertonic solution
solution with higher concentration, water moves out of cell, cell shrivels up
hypotonic solution
solution with lower concentration, water moves into cell, cell swells
isotonic solution
when 2 solutions have the same osmotic concentration
aquaporins
specialized protein channels for water
osmotic pressure
force needed to stop osmotic flow
hydrostatic pressure
pressure of the cytoplasm pushing out against the cell membrane
active transport
uses energy to power the movement of materials across a membrane against a concentration gradient
uniporters
transport a single type of molecule
symporters
transport 2 molecules in the same direction
antiporters
transport 2 molecules in the different directions
sodium potassium pump
active transport by antiporters to pump sodium into a cell and potassium out of a cell
1. ATP and 3 Na+ ions bind to pump
2. bound ATP is used to phosphorylate the pump
3. Na+ loses affinity to pump and diffuses away
4. 2 K+ ions are attracted to it and enters pump
5. dephosphorylation of protein, pushes K+ ions away
6. ATP binds again
coupled transport
transporting 2 substances across membrane; ex. membrane protein transports Na+ and glucose tags along by using the potential energy created by the sodium potassium pump
receptor-mediated endocytosis
cells have pits coated with protein clathrin that initiate when target molecules bind to receptor proteins
counter transport
active transport, where movement of a molecule across a membrane is matched by the movement of a different molecule in the opposite direction; ex. using potential energy of Na+ transport in sodium potassium pump to transport Ca+ ions in opposite direction
