Module 1- Cells as the basis for life Flashcards
Describe a prokaryotic cell
Unicellular organisms with no nucleus but rather DNA kept in a large loop. No membrane bound organelles everything floating in cytoplasm.
Benefits of eukaryotes
Allows specific processes to occur that require different environments at the same time. They are also less vulnerable to changes in environment.
Describe a Eukaryotic cell
Have a nucleus with membrane bound organelles with specific functions. can be both unicellular or multicellular.
What is the function and structure of nucleus
Stores genetic information, has large pores to allow RNA to read the DNA and make specific proteins
What is the function and structure of ribosomes
Synthesis of proteins, large SA:V speeds up diffusion rates
What is the function and structure of Mitochondria
Conducts cellular respiration to produce energy, folded surface increases SA to maximize energy produced.
What is the function and structure of Rough Endoplasmic reticulum
Transports, modifies proteins. Large size near nucleus membrane to optimize protein transport.
What is the function and structure of lysosomes
Uses enzymes to breakdown cellular waste, membrane unaffected by enzymes preventing escape into cell.
What is the function and structure of golgi body
Uses proteins to make compounds and protects compound with a membrane, part containing new compound able to separate from body for safe transport.
What is the function and structure of cell membrane
Semipermeable barrier allowing only specific chemicals in and out, thin pores allow movement of molecules.
What is the function and structure of vacuoles?
Storage spaces for compounds, can absorb water, sugars, and wastes.
What is the function and structure of Chloroplasts
Site of photosynthesis, making glucose, contains chlorophyll to do photosynthesis, has temporary storage.
What is the function and structure of Cell walls
Rigid shape for cell, made of strong cellulose preventing over absorption of water.
What is the function and structure of Smooth Endoplasmic Reticulum
Synthesis of lipids, large size allows for transport of proteins and lipids efficiently.
Examples of types of organisms:
Unicellular: Cyanobacteria, paramecium
Multicellular: Humans, plants
Colonial: Portuguese Man O’ War, Dog Vomit Slime Mould.
What does a cell membrane comprise of
A phospholipid bilayer with hydrophyllic phosphate facing out and hydrophobic lipids facing inward. Proteins scattered throughout.
How is the membrane ‘fluid’
Kept at low temps from lipids, proteins free to drift, very flexible and elastic
What is diffusion?
Substances are able to move in and out of a membrane along concentration gradient (for cells: lipid soluble substances)
What is facilitated diffusion
Non soluble in lipid substances diffuse into the cell via channel proteins.
What is active transport?
Energy is used to transport materials into the cell via a ‘protein pump’. uses ATP. Goes against concentration gradient.
What are Aquaporins
Channel proteins that allow water to move in and out of the cell
What is Passive transport
Movement of substances along the concentration gradient, no energy used (facilitated diffusion and diffusion)
What is osmosis?
Diffusion involving water. follow concentration gradient
Difference between Monosaccharides and Polysaccharides?
Monosaccharides are simple sugars made of one saccharide (basic unit for complex carbohydrates) Polysaccharides are made of multiple saccharides in a chain making more complex carbohydrates.
What is cytosis?
The movement of large molecules across a membrane, always requires energy
What is Exocytosis?
Moving large molecules out of the cell
What is Endocytosis?
Moving large molecules into the cell
What is an enzyme?
Biological catalysts that bound to substrates to make their reactions more efficient. Highly specific only able to conduct one type of reaction.
Structure of enzymes
Proteins with an active site which is the only place substrates can bond to.
What is the Lock and Key model
Rigid structure with only one type of substrate being enabled to bond exactly
What is the Induced fit model
Active site isn’t entirely rigid and slightly changes to bond the substrate perfectly.
Environmental impacts to enzymes
High temps and inadequate pH’s denatures the enzyme changing the shape and making them unable to bond with substrates. Low temps slow down particles reducing collisions and reaction rates.
How does substrate concentration impact rate of reaction
Reaction rate increases as substrate concentrations increase until it reaches a point of saturation (maximum enzyme capacity)
Importance of SA:V ratio
Larger cells have more energy needs but larger cells have a lower SA:V so percentage of energy absorbed is lower.
What is the concentration gradient
Particles naturally move from high to low concentrations to achieve equilibrium.
Physical properties preventing diffusion into cells
Boiling point, size, surface area. Small molecules pass through the membrane by simple diffusion but large molecules require facilitated diffusion or active transport.
Chemical properties preventing diffusion into cells
non charged molecules can freely diffuse but charged ions require channel proteins. Polarity (water solubility) can’t pass hydrophobic lipids also requires channel proteins.
How is Energy Produced
Energy is stored in the form ATP when an unstable phosphate breaks off this produces energy ATP becomes ADP.
How is ATP produced
Through Glycolysis and Krebs cycle breaking down complex molecules into simple molecules rebinding the third phosphate to ADP turning it back to ATP.
What nutrients do cells require
Water for transport and reactions, Carbon Dioxide for photosynthesis and oxygen for respiration, Salts for chemical reactions, Carbohydrates for energy, Lipids for hormones, proteins for structure and enzymes, Nucleic acids for genetic information.
What wastes do cells produce and why are they bad
Carbon dioxide- creates carbonic acid damaging natural pH
Ammonia - toxic, changes pH to basic
Water - too much damages the cell and prevents solvent to be absorbed.
How are wastes removed in cells
Carbon dioxide is absorbed by the blood and diffused in breathing.
Ammonia and Water are both excreted via urine.
Waste removal by lungs
Removes Carbon Dioxide and water from the blood through diffusion from the alveoli, they are then breathed out.
Waste removal by sweat glands
Urea, water, and salt are all released through small pores in the skin.
Waste removal by Liver and intestines
Dead/old blood cells are broken down by liver into bile which is then released out of the body by the large intestine.
Waste removal by Kidneys
Urea, salts and water are removed from blood and released as urine.
What is Photosynthesis?
Light dependent phase: Requires light, splits water from light energy occurs in grana
Light independent phase: uses products from dependent phase, occurs in stroma, produces glucose in calvin cycle
What is Aerobic Respiration
Glycolysis: Splitting of glucose into pyruvates produces two ATP
Krebs cycle: Within mitochondria, uses pyruvates to generate 34 ATP molecules
What is Anaerobic Respiration
Respiration without oxygen Glycolysis doesn’t require oxygen
What is fermentation
Glycolysis occurs but lack of oxygen means Krebs cycle doesn’t forming an alcohol or acid (Ethanol, Lactate)
