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
- Non-competitive Inhibition
o Involves an allosteric site: regulatory site
o Substance that reduces activity of an enzyme without entering an active site
o By binding elsewhere on the enzyme – changes the shape of enzyme
o Prevents binding of substrates
o Reversible – remove inhibitor, shape goes back
o Feedback inhibition
Understand what is meant by coupled reactions
- Exergonic reactions are coupled with endergonic reactions in order for the energy released from the exergonic reactions to be stored or used in powering endergonic reactions
- If not then energy produce cannot be used by cell to do work
Main compound responsible for coupling?
- ATP
Endorgenic coupling
- Changes from ATP to ADP (phosphate breaks off)
- P still in cell but not attach to molecule
- anabolic
Ca
Exergonic coupling
- Capture floating Phosphate to create ATP from ADP
- Happes when cell has energy derived from food
- Catabolic
Active site
- Part of an enzyme molecule where a substrate molecule attaches (by means of weak chemical bonds)
Aerobic
- Requiring oxygen
Anaerobic
- Does not require oxygen
- ATP is derived from oxidative phosphorylation without O2
- Instead of dumping electrons to O2 they go to Nitrate NO3, SO4 sulfate, and carbon CO3
Fermentation
- Alternative to respiration when organisms runs out of O2 or aren’t able to get enough of it needed for cells to keep on making energy
- Reduction of pyruvate to alcohol or lactic acid
- Produce little ATP without need of O2
- Efficiency: 2.1 %
- End result is inorganic compound
- Most goes to waste product
Respiration
- The transport of oxygen from the outside air to the cells within tissues, and the transport of carbon dioxide in the opposite direction
Mitochondria
- Organelle in eukaryotic cell
- Where cellular respiration occurs
- Enclosed by two membranes where most of the cell’s ATP is made
Oxidative Phosphorylation
- Production of ATP using energy derived from the redox reactions of an electron transport chain
- Third major stage of cellular respiration
Redox Reaction
- Movement of electrons from one molecule to another
- Oxidation Reduction
Oxidation
- Loss of electrons from a substance involved in a redox reactions
- Always accompanies reduction
Reduction
- Gain of electrons by a substance involved in a redox reactionis
- Always accompanies oxidation
Cytochromes
- electron transport protein
- Responsible for the generation of ATP via Electron Transport System ETS
- pigments
Chemiosmosis
- Energy coupling mechanism
- Uses energy of hydrogen ion H+ gradients across membranes to drive cellular work, such as the phosphorylation of ADP
- Powers most ATP synthesis in cells
Know the overall chemical equation for aerobic respiration.
C6H12O6 + 6O2 -> 6CO2 + 6H2O + Energy (ATP)
3 parts to Cellular/Aerobic Respiration
- Glycolysis
- Krebs cycle
- ETS
Glycolysis
- Glucose is broken down into pyruvic acid (pyruvate) releasing electrons (NADH) and ATP
- Simple sugar like glucose (mono) broken down half, into compound pyruvic acid
- End result: 2 ATP and 2 NADH
Krebs Cycle
- Pyruvate is oxidized to CO2 releasing more electrons
- End result:
- 2 NADH
- 2 [CO2] turn all sugar into CO2
- 6 NADHH
- 2 FADH2
- 2 ATP
- [CO2]
- Atp produced through substrate phosphorylation
- Uses sugar to get energy but not to build anything
ETS
- Electron transport system
- The released electrons are used to make ATP
- Way of moving electrons through the cell in such a way that flow of electrons produces enough energy so that the cell make ATP
- Requires membrane
- Uses cytochromes
- Requires oxygen as final electron accepter
- Results in formatioin H2O
- Final dumping ground from all electron – O2 gets turn into H2O
The starting reactants of Respiration
- Simple glucose, monosaccharide – glycolysis
- Kreb cycle – AcetylCoA to CO2
- ETS – CO2 to ATP
The end product of Aerobic Respiration
- ATP (energy)
ATP Released in each part of Aerobic Respiration
- Glycolysis – 2
- Kreb Cycle – 2 atp
- ETS – 28 ATP
- Total of 32 ATP per glucose per book
- total of 36 per PowerPoint and 32 from ETS PER LECTURE
- Energy conversion is approximately 39% ATP made rest heat.
Understand the roles of NADH and FADH
- Used as electron sources to power the formation of ATP in the mitochondria
Understand where in the cell, respiration takes place.
- mitochondria
Understand the role of oxygen in respiration.
- energy stored in NADH could not be harnessed for ATP synthesis
- ETS system requires oxygen as a final electron acceptor for ATP to be created
- It is the final dumping ground of all electrons which gets turn into water
Understand what happens in cells undergoing fermentation.
- Muscle tissue fails to keep up enough O2 for the energy demands of cells
- Animal cell: end product: buildup of lactic acid in muscle cells
- Pain stimulant-nerve pain
- Pain stays until blood system restore balance
Understand the concepts of catabolism, anabolism and metabolism
Metabolism
- All the reactions that the cell uses to get energy and to use it
- 2 parts: catabolism and anabolism
Catabolism
- To get energy
- the reactions that breakdown large molecules (Carbohydrates) to smaller molecules (Carbon dioxide and water) and Release Energy
Anabolism
- to use energy
- the reactions that use energy to make large molecules (proteins) out of small ones (amino acids)
3 Catabolic Stages
- Hydrolytic stage
- Degradative stage
- Oxidative stage
Hydrolytic stage
- Happens outside the cell
- Break up big molecule to smaller
- starch to sugar
- proteins to amino acid
- lipids to fatty acid
Degradative stage
- happens in cytoplasm
- ATP made by substrate phosphorylation
- Glycolysis and krebs cycle
Oxidative
- Happens in mitochondria
- ATP made by oxidative phosphorylation
- Electron flow is producing ATP
- End result of ETS is always ATP production
- Requires oxygen
Catabolism and Anabolism
- Atp produced during catabolic reactions is used to make new cell material
- Starting material are intermediate compounds of glycolysis and krebs cycle
- The cell’s METABOLIC POOL
Metabolic Pool
- Cells need to make new cell membranes in order to divide and needs fatty acids to make phospholipids. Fatty acids are made from acetyl-coA
- If metabolic intermediates are used they need to be replaced: the pool has to stay full
- Needs to be balanced: cells needs for growth and need for energy
Chloroplast
- Organelle found in plants and photosynthetic protists
- Absorbs sunlight and uses it to drive the synthesis of organic molecules (sugars) from carbon dioxide and water
Chlorophyll
- Green pigment located within the chloroplasts of plants, algae, and certain prokaryotes
Carotenoids
- Orange pigments synthesized by plants, algae, and cyanobacteria.
Xanthophyll
- Typical yellow pigment of leaves
- Oxygenated carotenoids that are synthesized within the plastids
- Does not require light for synthesis
- Present in all young leaves as well as in etiolated leaves
Grana
- The stacks of thylakoids embedded in the stroma of a chloroplast
Thylakoids
- Flattened membranous sac inside a chloroplast
- Contain chlorophyll
- Stack = granum
Stroma
- Dense fluid within the chloroplasts that surrounds the thylakoid membrane
- Involved in synthesis of organic molecules from carbon dioxide and water
- Where sugars are made by enzyme of Calvin Cycle
Stoma
- Pore surrounded by guard cells in the epidermis of a leaf
- When stomata are open, CO2 enters a leaf and water and O2 exits
- Plants conserves water when its stomata are closed
Mesophyll
- Green tissue in the interior of a leaf
- A leafs ground tissue system
- The main site of photosynthesis
Know where in the plant and where in the cells photosynthesis takes place.
Where in the plants does photosynthesis takes place?
- The Green Leaves
- Mesophyll
Where does Photosynthesis in the cells takes place?
- Chloroplast
o Substructure of another cell/always inside of another cell
o Consists of layer of membrane thylakoid
Inner most membrane of chloroplasts
Contains chlorophyll
Pigment responsible to capture most sunlight
Know the major differences between the light-dependent and light-independent reactions of photosynthesis.
Light – dependent
- Sunlight must be present
- ATP is made through oxidative processes
- Water H2O is a source of electrons
- As a result O2 is a waste product
- Cell is making ATP and NADPH
- Take place in Thylakoid (dependent in intact membrane)
Where does NADPH and ATP gets made?
- Outside of thylakoid in the Stroma
Know where in the chloroplasts the different reactions of photosynthesis take place.
- Chlorophyll - absorbs sunlight
- Stroma - light independent reaction, where ATP and NADPH is made
- thylakoids - site of light dependent reactions
Know the overall chemical reaction for photosynthesis.
6CO2 + 12H2O -> C6H12O6 + 6O2 + H2O
Be able to describe what happens to photosynthesis in situations of high temperature and low humidity
Transpiration
- C3/normal plants wilts
- Imbalance in gasses – Low CO2 and High O2/ calvin cycle doesn’t work
- Runs backwards; starts chewing up sugar and producing more CO2
- Stoma closes, but cells is still photosynthesizing
- Build up of O2 in intercellular space/ closed pores can’t get out
- Tropics – C4 plants survive – corn, sugarcane, tropical grasses
Photosynthesis is propelled by gas exchange
- By pores of leaves
- CO2 comes in and O2 comes out
- Space filled up with water
- Xylem conducts water from roots to leaves
- If water dissipates more than ability to make – plant wilts
Difference in C3 C4 and CAM plants in Calvin Benson Cycle
- C3 – Everything happens same time same place
- C4 – spatial separation of CO2 fixation vs Rest of cycle
o Separate cells - CAM – temporal/time separation of CO2 fixation vs rest of cycle – pineapple
- End result is Sugar
Where is sugar made during photosynthesis?
-stroma of the chloroplast
Enzymes have the effect of doing what inside cells ?
- Enzyme is a biological catalysts and Lowers the Activation Energy of reactions so they happen more often, with greater ease
What is the active site of an enzyme?
- Active site is the part of the enzyme molecule where a substrate molecule attaches (by means of weak chemical bonds)
- Typically a pocket or groove on the enzymes surface
What kind of molecule is an enzyme?
- protein
How does protein structure and internal binding affect enzyme function?
- Structure is important in forming active sites – conformation
- The form and charges are important in binding
- It has to fit with its substrates as a lock and key
- Specific enzyme and compound
How do environmental effects influence enzyme function?
- Temperature, pH, ionic strength
- It will change the structure and function of proteins
What is meant by competitive inhibition, give an example.
- A look alike reactants binds with an active site and prevents the proper substrates to bind with the active site.
- Poison, insect and reptile venoms, and neurotoxins
- Irreversible; permanently inhibits enzymes
What is the allosteric site and what does it do?
- Regulatory site
- The place on an enzyme where a molecule that is not a substrate binds to change the shape of the enzyme/active site so that no other may bind with it but the proper substrate
- Reversible
- Non-competitive Inhibition
What is non-competitive inhibition, give an example
- Substance that reduces the activity of an enzyme without entering an active site
- Binds elsewhere on the enzyme
- Changes the shape of enzyme
- Reversible
- Cyanide, potassium cyanide
Which of the following reactions is correct
a) ATP + energy —– > ADP + Pi
b) ADP —– > ATP + Pi + energy
c) ATP —– > ADP + Pi + energy
d) ADP + energy —–> ATP +Pi
C
In aerobic respiration what has to be present to release energy from NADH
- Oxygen
Glycolysis where in the cell
- Cytoplasm
What causes the burning sensation and fatigue during rapid exercise?
- Lactic Acid
- Lack of O2
Biological catalysts are called what
- Enzymes
The by-product (waste) of the Krebs cycle is
- CO2
The products of glycolysis are
2 ATP and 2 NADH
ATP made during glycolysis is made by what process
- Substrate-level phospholyration
Where in eukaryotic cells does oxidative phosphorylation take place
- mitochondria
What is the purpose of fermentation
- complements glycolysis
- Makes it possible for ATP to be continually produced in the absence of oxygen
- By oxidizing the NADH produce in glycolysis
The greatest contribution of electrons to the ETS comes from _______________?
NADH and FADH2
The compound which feeds into the Krebs cycle is _______________?
Acytel-CoA
What is catabolism? List some examples of catabolism
- To get energy
- Glycolysis
- Citric acid cylce
- Breakdown of muscle protein in order to use amino acids as substrates for gluconeogenesis
- Breakdown of fat in adipose tissue to fatty acids
- Proteins to amino acids
- Proteins to glucose
- Triglycerides to fatty acids
What is anabolism? List some examples of anabolism
- To use energy
- Synthesizing glucose
- Build biological molecules
- Amino acids to polypetides (proteins)
- Glucose to glycogen
- fatty acids to triglycerides
How many ATP are produced from the electron transport chain alone ( only oxidative phosphorylation) from one molecule of glucose
- 32 ATP
How many ATP molecules are generated for each molecule of glucose in aerobic respiration
- 36 ATP per glucose molecule per lecture
- Total of 32 for Aerobic Respiration per book
