Bio Exam #2 Flashcards
what’s the cell theory?
-All living organisms are made of cells
-cell = basic unit of life
-All cells arise from preexisting cells that have divided
Ribosomes
-site of protein synthesis
There's two kinds -Free ribosomes (in cytosol) -bound ribosomes (bound to ER)
-Structure: rRNA and protein in nucleus not organelles
Endoplasmic Recticulum (ER)
-Network of membranous tubules and sacs
-function: biosynthetic factory
-structure: membrane continuous with outer nuclear envelope
-lumen: inside
Golgi apparatus
- A receiving, sorting, shipping “machine”
Function:
-modify ER proteins
-polysaccharide synthesis
-sorting and packaging into vesicles
–cis face = receiving side
–trans face = shipping side
Lysosome
-Digestive compartment with hydrolytic enzymes
Function:
Phagocytosis
Autophagy
-helps in digestion, eats broken parts of cells to obtain nutrients for something else, “food vacuum”
why is the plasma membrane described by the fluid mosaic model?
the individual phospholipid molecules making up the bilayer can move around making the membrane structure flexible and constantly changing in shape. Mosaic because the embedded proteins in the bilayer resemble tiles of a mosaic due to their varying shapes, sizes and pattern.
what’s the difference between an integral and peripheral protein?
Both are passive transport
Integral protein:
-lets specific molecules pass through membrane
-moves down gradient
ex: ion channels, H2O
what’s the difference between active and passive transport?
Active transport:
-moves solute in and out the cell
-potassium = inside cell
-sodium= outside cell
passive transport:
-facilitated diffusion
-moves molecules down gradient
-can also change shape to bind with molecules to move down gradient
how does an animal cell behave in a hypotonic, isotonic, and hypertonic environment?
hypotonic:
-water enters the cell = lysed
isotonic:
-water moves in and out at same rate = normal
hypertonic:
- water leaves cell = shriveled
Explain how phagocytosis, pinocytosis, and receptor-mediated endocytosis work.
Phagocytosis:
- “cell eating”
- cell membrane pinches food participles outside the membrane
- that later becomes a food vacuole
Pinocytosis:
- “cell drinking”
-cell membrane pinches solutes outside the membrane into a coated pit (coated protein)
-that later becomes a coated vesicle
Receptor-Mediated Endocytosis:
-“magnets” for specific things
- coated vesicles with specific solutes bound to a receptor
- Recycles receptors after the solute is inside the cell
how does a plat cell behave in a hypotonic, isotonic, and hypertonic environment?
Hypotonic:
-water enters cell
-stops further water uptake
-turgid= frigid = healthy plant
isotonic:
-water enters and leaves as it enters
-flaccid= limp= plant sagging
hypertonic:
-water loss at a great amount
-membrane pulls away from cell wall
-Plasmolyzed = PLANT DEATH
what’s the difference between endocytosis and exocytosis?
endocytosis:
-cell takes in molecules and particle matter by forming new vesicles from plasma membrane
exocytosis:
-cell ships molecules by fusion of vesicles with plasma membrane
what is metabolism?
sum of organism’s chemical reactions
Does metabolism reach equilibrium in a living cell?
No and if it does all cell dies and you die too
what’s the difference between catabolism and anabolism?
Catabolism:
-breakdown pathway
-polymers to monomers
-“downhill” - energy released
Anabolism:
- Biosynthetic (building) pathways
- monomers to polymers
- “uphill” - energy required
what’s the difference between an exergonic and endergonic reaction?
Exergonic:
-energy released
-high reactants to low products
- spontaneous
- think “exit”
Endergonic:
-energy required
-low reactants to high products
-nonspontaneous
- think “enter”
what are the structures of ATP and ADP?
ATP:
Adenosine Triphosphate
-3 phosphate groups
-Ribose
-Adenine
(same structure as nucleotide)
ADP:
Adenosine diphosphate
-inorganic phosphate
-2 phosphate groups
-ribose
-adenine
- plus energy
what type of reaction is ATP hydrolysis and what is it?
Exergonic reaction because it uses its breaking down the ATP to ADP
ATP hydrolysis:
When ATP
why is ATP a renewable resources?
When ATP is used it turns into ADP, ADP can be recharged by adding a phosphate. So ATP can be recycled
how does ATP drive cellular work?
by transferring a phosphate group to another molecule (a process called phosphorylation)
how is energy stored in cellular fuels (organic molecules)?
As ATP
what type of organic molecules serve as fuel?
glucose
Define catabolism
The breakdown of complex organic molecules into simpler ones.
what four basic features do all cells share ?
1.chromosomes (DNA)
2.ribosomes
3.plasma membrane
4.cytosol
define oxidation and reduction
Oxidation:
-the addition of Oxygen
Reduction:
-the loss of Oxygen in a reaction.
what is meant by the term glucose oxidation?
-The breakdown of glucose in the presence of oxygen
- C6H12O6 + 6O2 ➡️ 6CO2 + 6H2O + energy.
describe the process of glycolysis?
“Sugar splitting”
-10 step process catalyzed by enzymes
-glucose (a 6 carbon sugar) is split into two molecules of the three-carbon sugar pyruvate.
compare a prokaryotic cell and a eukaryotic cell
prokaryotic cell:
1.does not have a nucleus
2.small in size
3.no membrane bound organelle
4. can’t have a cell wall
5. has ribosomes
6. no DNA
Eukaryotic cell:
1. has a nucleus
2. bigger in size
3. membrane bound organelle
4. could have organisms with cell wall
5. has ribosome
6. has a DNA material
Nucleus
Function: makes ribosomes, makes DNA and protein, stores heredity info, control cell
structure: double membrane ( nuclear envelope)
smooth and rough ER
Function: biosynthetic factory
structure: membrane continues w/outer nuclear envelope
where does glycolysis occur in the cell?
the cytoplasm
Does glycolysis require oxygen in order to occur?
No
peroxisome:
Function: break down fatty acids; liver- detoxify
Structure: metabolic compartment containing enzymes
what are the products of glycolysis?
2 ATP, 2 NADH, and 2 pyruvic acid molecules.
Mitochondria
Function: cellular respiration
structure: “powerhouse” of cell
what happens to the electrons in glycolysis?
They are transferred to the electron transport chain by NADH and FADH₂.
Identify the specific location in a eukaryotic cell where the following processes occur: glycolysis, pyruvate oxidation, Krebs cycle, ETC / chemiosmosis
Glycolysis:
-Cytoplasm
Pyruvate oxidation:
-Mitochondria (matrix)
Krebs cycle:
-Mitochondria (matrix)
ETC:
-Cristae (folds)
Chemiosmosis:
-Cristae
chloroplast
Function: photosynthesis
Structure: capture light E; photosynthetic eukaryotic (plant & algae)
where are ribosomes found in?
in the cytoplasm of plant, animal, and bacteria cells
what is the function of ribosomes in the cell?
to produce protein
what is the overall function of the cytoskeleton?
- organize structure and cell activities
- mechanical support - shape
- cell motility - change in cell location and movement of cell parts
- anchor/ positions organelle
- manipulate plasma membrane - inward bending to form vacuole or vesicles
describe structure and function of the three components
- Microtubule
Function: cell shape, cell motility, cell
division, organelle movement, vesicles
“highways”Structure: hollow tubes, diameter = 25nm 2/lumen, made of a & b tubulin
- Microfilament
Functions: cell shape, muscle
contraction, cytoplasmic streaming,
cell drawing, animal cell divisionStructure: 2 intertwined strands, diameter = 7nm, made of actin
- Intermediate
Functions: cell shape, nuclear
lamina- line interior of nuclear
envelope, organelle positioningStructure: coiled protein cables, diameter = 8-12 nm, protein vary: keratin
What’s the summary equation for cellular respiration?
C6 H12 O6 + 6O2 –> 6CO2 + 6H2O + ATP
what is oxidized and reduced in the summary equation of cellular respiration?
oxidized:
-glucose
reduced:
-oxygen to form CO2 and water.
Explain how ATP is produced by chemiosmosis in the process of oxidative phosphorylation in the mitochondria
-hydrogen ions travel across the membrane
-Chemiosmosis involves the pumping of protons through specific passageways in the membranes of the mitochondria from the inner to the outer space.
what is ECM ? what is it made of ? whats its function?
ECM: Extracellular matrix
it’s made of protein and polysaccharides.
Function:
1. support
2. adhesion
3. movement
4. regulation
how are microtubules organized in an animal cell?
microtubules are organized in an animal cell by the centrosome
what are the three types of animal cell junction? and how do each function ?
- Tight junction: prevents leakage of material through space between cells
- Desmosome: “rivet” fastening cells together
- Gap junction: cytoplasmic channel between adjacent cells
how many ATP molecules are produced for each glucose molecule in oxidative phosphorylation?
38 ATP molecules
what are the properties of an enzyme?
- Catalyst: speed up chemicals without being consumed or chemically changed
-typical end in an “ase”
-highly specific
- active site: pocket for substrate interaction and catalysis
How do enzymes work?
- substrates enter active site
- substrates are held in active site by weak interactions.
- the active site lowers Ea (activation energy)
- substrates are converted to products
- products are released
- active site is available for new substrates.
