Exam 2 Flashcards
Compare Prokaryotes and Eukaryotes.
Prokaryote cells have no membrane bound nucleus and no membrane bound organelles.
Eukaryote cells have a membrane bound nucleus, which houses DNA, and have membrane bound organelles which house specific cell processes.
Describe the structure of a virus.
Capsid- protein coat nucleic acid- DNA or RNA Some have an envelope that surround the capsid. They are made of lipids, proteins, and glycoproteins. Lipids come from the host cell membrane. Viruses are not considered organisms because they: *lack cellular structure *lack independent metabolism *lack independent replication *described as active or inactive *infect by transferring genetic material into cell
What are the similarities between Prokaryotes and Eukrayotes?
They both have:
- plasma membrane
- cytosol (jelly like fluid inside cell)
- chromosomes (carry genes in the form of DNA), Prokaryotes are circular and Eukaryotes are Linear
- Ribosomes that make proteins
What are membranes?
membranes are phospholipid bilayers. Polar hydrophilic heads face outward. Nonpolar hydrophobic tails face inward.
What is a Vesicle?
Vesicles are small membrane bound sacs. They store and transport materials. They form off of the endomembrane system
What is a Nucleus?
A nucleus houses chromosomes; chromosomes discrete units of organized DNA. The nucleolus: rRNA synthesized here. Nuclear envelope is two bilayers
What is the Endoplasmic Reticulum and what are its two types?
It consists of two phospholipid bilyaers embedded with proteins.
Two types:
Rough ER- outer surface contains ribosomes. Produces proteins that will be secreted. Manufactures membranes by producing membrane proteins and phospolipids.
Smooth ER- outer surface lacks ribosomes. Contains enzymes that synthesize lipids. Contains enzymes that help detoxify drugs and poisons. Stores calcium ions which are used as signaling molecules.
Describe the Fluid Mosaic Model.
It is a model to describe the structure of the cell membrane. Membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids.
What are the components of a cell membrane?
- Phospholipid bilayer, polar hydrophilic phosphate heads, nonpolar hydrophobic fatty acid tails
- transmembrane proteins (integral proteins)
- requires energy inform of ATP
- Sodium Potassium pump: one type of active transport system
what is endocytosis and its 3 types?
The taking in of matter by a living cell invagination of its membrane to form a vacuole. 3 types:
- Phagocytosis (eat) is the ingestion of bacteria or other material by phagocytes and amoeboid protozoans.
- Pinocytosis (drink) is the ingestion of liquid into a cell by the budding of small vesicles from the cell membrane
- Receptor-mediated Endocytosis is a process by which cells absorb metabolites hormones, proteins, sometimes viruses, by the inward budding of plasma membrane vesicles containing proteins with receptor sites
What is exocytosis?
a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane
describe Osmosis.
Diffusion of water across a permeable membrane. Water moves across a membrane from lower solute concentration to higher solute concentration
Describe diffusion.
The net passive movement of molecules from high concentration to lower concentration until it is uniform throughout
Describe facilitated diffusion.
Transport of proteins speed the passive movement of molecules across the membrane
What is the Golgi Apparatus?
Consists of flattened membranous sacs that are not physically connected. Collects, packages, and distributes molecules that are made at one location and used at another
What is a Lysosome?
Membranous sac of hydrolytic enzymes. They arise from the Golgi Apparatus. Contains enzymes that catalyze breakdown of macromolecules. Can also destroy cells or foreign matter engulfed by cells
What are Vacuoles?
Large vesicles derived from ER and Golgi. Their functions are:
Food vacuole
Contractile vacuole
Central vacuole
What are microbodies?
Enzymes bearing vesicles. One way for Eukaryoktic cells to organize their metabolism. An example is Peroxisome which contains enzymes function to oxidize fatty acids and detoxify harmful chemicals (like alcohol). It is a byproduct of reactions, hydrogen peroxide (enzyme catalase furhter breaks down hydrogen peroxide)
Describe the Mitochondria.
It is found in all types of Erukaroyitc cells. It is the site of cellular respiration - metabolizes sugar to get ATP. It is surrounded by 2 membranes - has its own circular DNA and has its own ribosome
Describe the Chloroplast.
It is found in photosynthetic Eukaryotic cells (plants and some protist). It is the site of photosynthesis - use energy from sun to generate sugars. Has a green pigment and is surrounded by 2 membranes. It has its own circular DNA and its own ribosomes.
What is the Endosymbiont Theory?
The Mitochondria and Chloroplasts evolved as a consequence of symbiosis between an early ancestor of eukaryotic cells and a prokaryotic cell.
Mitochondria: oxygen using, non photosynthetic prokaryotic
Chloroplast: photosynthetic prokaryotic
the evidence: circular DNA, 2 membranes, ribosomes are similar to prokaryotic ribosomes, replicate independently of cell chromosomes and similar to bacterial replication
What are membrane proteins?
Perform different functions: membrane receptor proteins relay signals between the cell’s internal and external environments. Transport proteins move molecules and ions across the membrane.
What is potential energy?
It is stored energy in an object or system and is not relative to an objects environments.
What is kinetic energy?
It is when an object is in motion. It is relative to other moving and stationary objects in its main environment.
Name the steps in all of cellular respiration.
- Glycolisis. Changed to Pyruvate. 2 ATP used, 4 ATP made, 2 NADH made.
- Transition (pyruvate oxidation). 2 Pryuvate changed to Acetyl coA and 2 CO2. 2 NADH made.
- Krebs Cycle. 2 acetyl coA changed to 2 coA and 4 CO2. 2 ATP made, 6 NADH made and 2 FADH2 made.
- Electron Transport. H+ pumped out. O2 and H+ changed to H2O then H+ back in. All NADH made to NAD+, all FADH2 made to FAD, 32-34 ATP made (ATP synthase is an enzyme)
What are exergonic reactions?
release free energy, it is spontaneous
What are endergonic reactions?
aborbs free energy, is not spontaneous
Explain releasing energy.
ATP can release and store energy by breaking and reforming the bonds between its phosphate groups. This characteristic of ATP makes it exceptionally useful as a basic energy source for all cells
What are enzymes?
They are biological catalysts that speed up chemical reactions
What are the characteristics of enzymes?
- reusable, once reaction is over the enzyme is released to participate in another reaction
- highly specific, enzyme binds to specific substrate due to shape of active site
- require small amount because they are reusable
what are the cofactors of enzymes?
non-protein helpers for enzyme activity are often metal ions and usually found in active site.
What are coenzymes?
organic cofactors such as NAD+, FAD, b6 and b12 (vitamins)
What environmental conditions effect enzyme activities and why?
- optimal conditions favor most active shape for enzyme
- temperature increases the rate of reaction up to a point (if it’s too high it might denature)
- PH, hydrogen ion concentration can disrupt ionic interactions and hydrogen bonds holding protein together
- substrate concentration, if increased can lead to increased reaction rate up to a point
what is an inhibitor and it’s two types?
binds to enzyme and decreases its activity.
1. competitive, binds to an active
what is feedback inhibition?
product of metabolic pathway inhibits an enzyme in a previous step
what is Vmax?
velocity of enzyme
what is Km?
describes substrate concentration at which half enzymes active sites are occupied by substrate
Km= 1/2 Vmax
high Km must have a lot of substrate to saturate enzymes low Km only need small amount of substrate to saturate enzyme
explain glycolysis and its inputs and outputs.
extracts energy from glucose; occurs in the cytoplasm. Starts with 6 carbon molecule ends with two 3 carbon molecule of pyruvate. There are 2 steps; energy investment, and energy payoff.
inputs; 1 glucose (6 carbon molecule), 2 ATP, 2 NAD+
outputs; 2 pyruvate (3 carbon molecule), 4 ATP, 2 NADH
Explain the Pyruvate Oxidation Transition and its inputs and outputs.
occurs in Mitochondria, starts with 3 carbon molecule (pyruvate) and ends with 2 carbon acetyl coA. CO2 is released a byproduct.
inputs: 3 carbon molecule pyruvate, 2 NAD+
outputs: acetyl coA (2 carbon molecule), 2 CO2 and 2 NADH
Explain the Krebs Cycle and its inputs and outputs.
occurs in Mitochondrial matrix.
inputs: 2 acetyl coA, 6 NAD+, 2 FAD
outputs: 4 CO2, 2 ATP, 6 NADH, 2 FADH2
explain the Electron Transport Chain and its inputs and outputs.
series of membrane bound electron carriers embedded in the inner mitochondrial membrane, each chain acts as a proton pump.
inputs: NADH, FADH2, O2
outputs: NAD+, FAD, H2O, about 28 ATP
What is cellular respiration?
is a set of metabolic reactions and processes that take place int he cells of organisms to convert biochemical energy from nutrients into ATP
what does aerobic respiration require?
O2
what is anaerobic respiration?
uses electron acceptors other than O2, like Sulfer, nitrate, carbon dioxide
what is fermentation respiration?
does not use electron transport chain or Krebs.
1. glycolysis
2. regenerates NAD+
3. uses organic compound as final electron carrier
(kimchi, cheese, wine, ect)
what is Oxidation Phosphorylation?
uses an eletronchemical gradient of protons across the inner membrane of the Mitochondria to generate ATP from ADP
what is substrate level phosphorylation?
it is a type of metabolic reaction that results in the formation of ATP by direct transfer an donation of a phosphoryl to ADP
what is catabolism of protein?
amino acids undergo deamination to remove the amino group. The remainder of the amino acid is converted to a molecule that enters glycolysis or the Krebs Cycle
what is catabolism of fat?
fats are broken down to fatty acids and glycerol
what is photosynthesis?
uses energy from the sun to produce stored energy in the form of sugar
what are the 2 stages of photosynthesis
- light dependent reactions require light, makes ATP, reduces NADP+ to NADPH
- Calvin Cycle does not require light, makes compounds CO2, uses ATP and NADPH made in light reactions g
what is the site of photosynthesis?
The chloroplast
what is the stroma?
a semi fluid surrounding thylakoid membrane
what are the inputs and outputs of photosynthesis?
inputs: 6H2O, 6CO2, light energy
outputs: C6H21206 (glucose), 6O2
what are pigments?
molecules that absorb light energy in visible range
what are the pigments in chloroplast?
chlorophyll A has a primary pigment. Chloroplyll B has an accessory pigment. Carotenoids absorb light that chlorphyll pigments could not
what is photosystem 1 and 1?
Photosystem 1 is light dependent reactions. Is the second photosystem in photosynthetic light reactions of algae, plants and bacteria
Photosystem 2 is the first protein complex in the light dependent reactions of oxygenic photostynthesis located in the thylakoid membrane of plants, algae and bacteria
what is light harvesting complex (antenna)?
It is an array of protein and chlorophyll molecules embedded in the thylakoid membrane of plants which transfer light energy to one chlorophyll molecule at the reaction center of a photosystem
what is the reaction center?
Is a complex of several proteins, pigments, and other cofactors that together execute the primary energy conversion reactions of photosynthesis
what is RuBP?
It is an organic substace that is involved in in photosynthesis
how does ATP power cellular work?
When a phosphate group is transferred from ATP to a substrate molecule, the energy transferred can power cellular work
