Exam #2 Flashcards
Organelles –
structure inside a cell that is bound or surrounded by its own membrane
Cytoplasm
- the contents of a eukaryotic cell between the plasma membrane and the nucleus
- Consist of a semifluid medium and organelles
- Refer to the interior of a prokaryotic cell
Ribosomes
- Cell structure consisting of RNA and protein organized into two subunits and functioning as the site of protein synthesis in the cytoplasm
- In eukaryotic cells – ribosomal subunits are constructed in the nucleolus
Lysosomes:
contain digestive enzymes to degrade engulfed material
Chromatin:
Genetic material: DNA and Protein
Exergonic –
reactions that gives up energy
Catabolic
Endergonic
– requires work/energy
Anabolic
- Membrane-bound nucleus
Nucleus: surrounded by a double membrane
- Have holes
- Material inside cell: chromatin
- Chormatin: genetic material: DNA and protein
- Nucleolus: (another structure inside nucleu)
Know the principal differences between eukaryotic and prokaryotic cells
- Eukaryotic is bigger and has a nucleus and organelles; nucleus surrounded by double membrane; DNA house in nucleus
- Prokaryotic is small and has no nucleus or internal organelles; simple; dna free-floating
- Endoplasmic reticulum
o Long labyrinth like membrane that fills up good portion of cytoplasm
o Two kinds: Rough ER and Smooth ER
o Rough ER
Studded with ribosomes
Site of protein synthesis
o Smooth ER
No ribosomes
Site of lipid synthesis
- Golgi apparatus
o Protein Processing and packaging
o (secretory proteins)
o Responsible for taking protein made in ER and packaging them
- Mitochondria
o Cell powerhouse: site of ATP Synthesis
- Chloroplasts
o Absorbs sunlight to do photosynthesis o Leafy plants and algae only o Photosynthesis (ATP from sunlight) and CO2 incorporation
- Vacuole
o Big Storage ‘compartments’
o Starch, enzyme
o lysosomes
o Vesicle: small storage compartments
- Cytoskeleton
o Microtubules (tubulin)
o Microfilaments (actin)
o Centrioles
o Microtubules (tubulin)
Organize and move the organelles
Responsible for cell shape
Not bound by membrane
protein
o Microfilaments (actin)
Movement of the cell (pseudopodia) and organelles (cyclosis)
Movement of organelles within cells
o Centrioles
Organization of cell division
Organize formation of microtubules
Present during cell division
- Cilia and flagella
o Organs of locomotion
o Flagella
Long, relatively few per cell
Outside of cells
Whip back and forth and push through environment
o Cilia
Short, many thousands per cell outside
All move together pushing cell through environment
Can spin, travel straight, left, right, backwards, turn around.
- Membrane
o Aka Plasma Membrane, cytoplasmic membrane
o Membrane at the boundary of every cell that acts as a selective barrier to the passage of ions and molecules
o Consists of phospholipid bilayer with embedded proteins
Structure of phospholipid bilayers
o Phospholipid – lipid made up of glycerol joined to two fatty acids and a phosphate group with two non-polar hydrophobic tails and a polar hydrophilic head
o Outside and inside of cell is made of water therefore:
o Hydrophilic head is both facing outside of cell and inside of cell where water is
o And Hydrophobic tails are sandwiched between the two heads
-
Role of proteins in membranes
o Some outside, some inside
o Outside: peripheral protein, hydrophilic
o Inside: embedded: integral protein, hydrophobic
o Help cell interact with environment- ferry nutrients across plasma membrane
o Receive chemical signals from outside cell
osmosis
isotonic, hypotonic, hypertonic
- Osmosis
o Movement of water across a membrane in response to solute differences outside and inside the cell
o From more concentrated to less concentrated water
- Isotonic
o Has no effect on the passage of water into or out of the cell
- Hypotonic (osmosis)
o Will cause the cell to take up water
o Swell and Burst
o When solute is lower
- Hypertonic (osmosis)
o When solute is higher
o Shrink
o Animal cells without cell wall – shrank cell - crenation
o Plant cells – cell membrane separate with cell wall - plasmolysis
- Gradient
o The difference in concentration
- The three transport of diffusion
o Selective
o 1. Passive transport
o 2. Facilitated transport
o 3. Active transport
- Passive transport
o Simple diffusion (osmosis)
o Movement of solutes across membrane with a gradient (from higher concentration to lower concentration)
- Facilitated Transport
o Movement of solutes across membrane with a gradient dependent on presence of carrier proteins
o From higher concentration to lower concentration
o Without using energy of cell
o Membrane-assisted transport: endocytosis, exocytosis
Endocytosis
\: get into cell • Phagocytosis o Deformation of cell membrane to wrap around big object like and engulf foreign material – vacuole • Pinocytosis o Size difference o Small molecules but lots of them o Vesicles
Exocytosis
- Out of cell
- Cell produce material inside vesicle then fuse with membrane then comes out
- Reverse of endocytosis
- Active transport
o Movement of solutes across membrane against a gradient
o Requires transport protein and uses energy
Cell walls : difference between plants and animals and bacteria
- Most animals lacks cell wall
- Plants have cells walls made of cellulose (polysaccharide
- Bacteria have cell walls made of a polysaccharide: peptidoglycan
- Cells walls are made up of carbohydrates
Enzyme
- Biological catalyst
Catalysts
- Some other molecule that spreads reaction up without itself being change by the reaction
Activation Energy
- The amount of energy that reactants must absorb before a chemical reaction will start
ATP
- Adenosine triphosphate
- The main energy source for cell
Substrate
- Reactant
- A specific substance (reactant) on which an enzyme acts
- Each enzyme recognizes only the specific substrate or substrates of the reaction it catalyzes
Endproduct
- Products
Feedback Inhibition
- Method of metabolic control in which a product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway
- Loops all over the cell
- Way of the cell controlling what’s made or used without wasting resources
Phosphorylation
- Transfer of a phosphate group, usually from ATP, to a molecule
- Nearly all cellular works depends on ATP energizing other molecules by phosphorylation
Substrate Phosphorylation
- Formation of ATP by an enzyme directly transferring a phosphate group to ADP from an organic molecule
- Intermediates in glycolysis or citric acid cycle
Understand how enzymes work
- Lowers the Activation energy of reactions so they happen more often, with greater ease
- Removes randomness of interactions
Understand the factors that affect enzyme speed
- Temperature
- pH
- Ionic Strength
- Presence of any inhibitors or activators
Understand how enzymes are inhibited
Enzyme can be both activated and inhibited
- Activated – degradative reaction and synthetic reaction
- Inhibition – Competitive and Non-competitive
- Degradative Reaction
o Taking substrate and breaking it up
- Synthetic Reaction
o Take set of substrate/product and form a new one
- Competitive Inhibition
o A substance that reduces the activity of an enzyme by binding to the enzymes active site in place of the substrate.
o Competitive structure mimics that of the enzymes substrate (look alike)
o Irreversible
o Neurotoxins, poisons