cell transport, membrane and experiments Flashcards
passive transport
- movement of molecules without needing energy
- includes: simple diffusion, facilitated diffusion and osmosis
simple diffusion: through the lipid bilayer
facilitated diffusion: through channel and carrier proteins
osmosis: movement of water molecules across a membrane from a high concentration to a low concentration
3 ways passive transport occurs
- diffusion through lipid bilayer
- facilitated diffusion (through channel, through carrier)
diffusion through lipid bilayer
- allows free passage of some molecules
- straight through membrane
diffusion through channel
- molecules transported through central core
- e.g. H2O
- channel protein
open: are open all the time
gated: they open and close under certain conditions - like a conveyer belt
diffusion through carrier
- molecules attaches to the protein membrane
- will change shape to transport molecule
- suck in sneeze out mechanism
- carrier protein
- carries molecule across the cell membrane
active transport
- moves substances against concentration gradient
- low to high (up hill)
- requires energy
type of active transport
vesicular transport
- endocytosis
- exocytosis
endocytosis
- into the cell
- membrane folds around the particle (completely enclosed)
- vesicle suspends into cell cytoplasm
pinocytosis - taking in liquid
phagocytosis - taking in solids
exocytosis
- out of the cell
- vesicle forms inside the cell
- migrates to the cell membrane and fuses
- contents of vesicle then pushes out
cell membrane
- controls movement of materials into and out of the cell
- fluid mosaic model
- forms the boundary between the internal environment of the cell and the external environment
- selectively permeable
fluid mosaic model
- double layer of phospholipids
- mosaics made of proteins, glycoproteins, glycolipids and cholesterol
protein
- act as a carrier and receptor cities
- may control the movement of specific molecules into and out of the cell
- includes: channel protein, carrier protein, and receptor protein
glycolipids
act as a surface receptor and stabilize the membrane
- squares above the membrane
- hydrophilic tails inside the membrane
glycoprotein
- play an important role in cellular recognition and immune response
- within the membrane and has things coming out the top
cholesterol
- disturbs the closely packing of the phospholipids and regulates membrane fluidity
- hexagons within the membrane
receptor protein
- lock and key model
- specific to certain substances
internal environment
- cell membrane regulates the internal environment
- chemical reactions including respiration and photosynthesis happen here
- enzymes can perform their tasks
- toxic waste producers are removed to ensure they do not with chemical reactions in the cytoplasm
phospholipids
- water proof barrier
- phosphate head (hydrophilic)
- 2 fatty acid tails (hydrophobic)
- arranged as a bilayer
osmotic pressure
- the pressure created by the water moving across a membrane
- the more water the higher the osmotic pressure
hypertonic
high solvent outside the cells, water moves outwards, cell shrinks
hypotonic
low solvent outside the cell, water moves inwards, cell enlarges
isotonic
equal amounts of solvent and water
- cell stays the same
- numbers coming in are equal to the numbers going out
osmosis in animals
- shape of red blood cells is designs to maximize their surface area
- unicellular organisms have mechanisms that are able to remove excess water by forming pools in the cytoplasm called contractile vacuoles
- multicellular are bathed in isotonic fluid therefore can function effectively because there is no net movement of water into or out of the cell
osmosis
- from a dilute solute to a high concentration solution
- the movement of water molecules from a of low concentration to high solute concentration
- water moves into sugary things
solute
dissolvable substance
solvent
substances that dissolves the solute
water
solution
solvent and solute mixed together
blood cells
- if the plasma surrounding the blood cells becomes hypertonic water will move out of the cell and will shrink
- these then stick together and clog veins preventing oxygen reaching blood tissues
- if the plasma surrounding the cells becomes hypotonic the blood cells will swell and burst
- this is called hemolysis which reduces the amount of oxygen being transported
osmosis in plants
- plant cell vacuoles contain sap which is rich in solute
- when a hypotonic solution surrounds the cell water molecules diffuse into the cytoplasm and then the vacuole
- cells placed in solution whose solute concentration is lower then the sap water enters and becomes full turgor
- cell placed in solution whose solute concentration is higher then the sap water leaves and becomes full plasmolysis
diffusion
- movement of molecules from high concentration to low concentration
- doesn’t use energy
- takes place until the concentration reaches equilibrium
- further from the source the lower the concentration
diffusion gradient
decreasing concentration from left to right
factors effecting rate of diffusion
- concentration difference
- surface area
- membrane thickness: thinner the membrane the faster diffusion rate
- particle size: small particles diffuse faster
- temperature: increase in temp causes higher diffusion rate as they have higher kinetic energy
surface area to volume ratio
- ratio to cells surface area in relation to its volume
- maximizing surface area to volume ratio is important so transport systems can run efficiently in cells
- large surface area can absorb things faster
- leaves are flat to increase surface area to volume ratio
cells are small
- surface area allows a cell to gain or loose material quicker
- when they grow they divide so they don’t get too big
- as they get bigger it is difficult for them to exchange materials with their surroundings
- any cell larger then 100um materials can’t diffuse fast enough to support the reactions needed fro life
- cells in multicellular organisms are no bigger then 30um so they can exchange materials quicker and independently
- molecules with a larger surface area to volume ratio loose heat faster
some unicellular organisms have a contractile vacuole to remove excess water from their cells, why does water continually enter the cells? how does the water enter the cells? what is this process called?
because they have a large surface area/volume ratio and there is w high concentration on the outside and low on the inside the water enters through the cell membrane and it is called osmosis
why does the food dye in the hot water diffuse quicker?
Temperature is related to how fast the molecules are vibrating.
Therefore, in the hot water the molecules were vibrating faster than they were in the cold water.
This causes the dye in the hot water to diffuse quicker
quantitative
weight and length
qualitative
shape changed and became a little bit less shriveled
hydrophilic
a substance that tends to interact with and dissolve in water
hydrophobic
avoiding association with water
photosynthesis
process of transforming sunlight energy into chemical energy
photosynthesis équation
carbon dioxide + water + energy – glucose + oxygen gas
6CO2 + 6H2O – C6H12O6 + 6O2
leaf structure
- cuticle
- upper epidermis
- palisades layer (chloroplasts)
- spongy layer
- lower epidermis (indues guard cells and stomate)
stomate
opening
- open = gain H20
close = lose H2O
leaf adaptations
- large surface area = to absorb light
- thin = gasses don’t need to diffuse far
- contain chlorophyll = to trap light
- network of veins = to transport water and sugar
- have stomate = to allow gasses to diffuse in and out
chloroplast structure
- contain DNA and ribosomes
- outer membrane
- intermembrane
- stroma (liquid interior)
- granum (stacks of thylokaid membranes containing chlorophyll)
- thylakoid
2 phases of photosynthesis
- light dependent phase - occurs in the thylakoid membrane, splits water into hydrogen and oxygen ions
- light independent phase - occurs in the stroma, takes CO2 and combines with hydrogen ions and creates sugar
factors affecting the rate of photosynthesis
light - as light increases photosynthesis increases until it hits a flat line, chlorophyll is working as fast as possible and can’t work any faster, it can only absorb a certain amount of light at one time
carbon dioxide - rate of photosynthesis increases as carbon dioxide concentration increases, makes a big different as it is a reactant. at high concentration the rate of photosynthesis begins to slow as limiting factors other then CO2 become important
temperature - increasing temperature increases photosynthetic rate because of its effect on enzyme activity, however temperatures exceeding optimum will eventually decrease photosynthetic rate
enzymes
- catalyst that speed up biological reactions which are not consumed
- only complete specific jobs
- reusable
- reduces the activation energy of reactions
anabolic
joins 2 or more substrate molecules together
catabolic
break a molecules into smaller parts
lock and key model
- a substrate is drawn into the active sites of an enzymes
- substrate shape much be compatible with the active site in order to react
- enzyme modifies the substrate breaking down or joining together
induced fit model
- 2 substrate molecules are drawn into the active site
- the enzyme changes shape forcing the substrate molecules to combine
- the resulting end product is released by the enzyme which returns to its normal shape
factors affecting enzymes
temperature - enzyme activity increases with temperature due to increased particle speed = increased collision with enzymes and substrates
- if too hot enzyme denatures loosing its 3D shape therefore substrate won’t fit
enzyme concentration - rate of reaction increases more enzymes present
substrate concentration - rate of reaction increases and then plateaus with increasing substance concentration
- all enzymes are busy and need to wait
enzyme helpers
- cofactors
- inhibitors
- competitive inhibitors
- non competitive inhibitors
cofactors
- permanently or temporarily attaches to enzyme to change the shape
- helps to form the active site
inhibitors
- binds to the enzyme causing its shape to change preventing the substrate from binding
competitive inhibitors
- mimic true substance and fit into active site
- fits into active site but doesn’t do anything
- blocks the enzyme
non competitive inhibitor
- doesn’t lang in the active site but attaches and changes the shape
- substrate is unable to fit into the active site
- preventing function
respiration
- series of chemical reactions that involve a reaction between glucose and oxygen to produce carbon dioxide water and energy
- needed to grow, reproduce, move and carry out fundamental maintenance and repairs
aerobic respiration equation
glucose +oxygen – carbon dioxide + water + ATP
C6H12O6 +6O2 – 6CO2 + 6H2O + energy
aerobic respiration
- requires energy
- glucose is completely broken down into carbon dioxide and water
aerobic respiration steps
glycolysis
citric acid cycle
- oxygen combines with pyruvate which produces carbon dioxide water and ATP occurs in the mitochondrion
glycolysis
- glucose is broken down to pyruvate with a yield of 2 ATP for each glucose molecule
- occurs in the cytoplasm
anaerobic respiration
- doesn’t require oxygen
lactic acid fermentation
C6H12O6 – 2CH3CH(OH)COOH + ATP
glucose – lactic acid and energy
- in animals
alcohol fermentation
glucose – alcohol + carbon dioxide + ATP
- in plants
anaerobic respiration steps
glycolysis
- pyruvate goes to ethanol + carbon dioxide and lactic acid when oxygen is unavailable
ATP
- universal energy carrier for cells
- small (move around easily)
- rechargeable and reusable
- captures energy from broken down glucose
- releases energy to drive chemical reactions
- composed of adenine, ribose and 3 phosphates
- energy is used for atp synthesis
biomolecules
- carbohydrates
- proteins
- lipids
- nucleic acid
carbohydrates
- carbon hydrogen and oxygen
carbs function
- break down sugars which are delivered to cells
- cells use the energy for movement, growth and cells activities
- quick energy and energy storage
carbs monomer
- monosaccharides
carbs examples
monosaccharides - simple sugars - glucose fructose disaccharides - 2 monosaccharides (double sugar) - sucrose polysaccharides - many sugars molecules - chains of glucose - glycogen
carbs structure
chains of glucose monomers joined together
carbs found
- fruits bread pasta
proteins
carbon hydrogen oxygen nitrogen and sulfur
proteins function
- control chemical reactions
- transport in the membrane
- build maintain and replace tissues in your body
protein monomer
- 20 amino acids
protein examples
- enzyme reactions
- membrane structure
protein structure
- long necklace with different shaped beads
- each bead is a small amino acid
- these amino acids join together to make thousands of proteins
proteins found
- meat
dairy
nuts seeds
lipids
carbon hydrogen and oxygen
lipids function
- store energy
- hormones
- water proofing
- shock absorber
- insulation
- protect our organs
lipids monomers
- fatty acids
- glycerol
lipids structures
3 fattty acid tails attached to a glycerol
- triglycerides
lipids examples
- oils
fats
lipids found
butter meat cheese oil
nucleic acid
carbon hydrogen oxygen nitrogen sulfer phosphorus
NA function
- store genetic code
NA monomer
nucleotide
NA examples
DNA RNA
NA structure
made of nucleotides joined together
prokaryotic
- pili
- chromosome DNA
- ribosomes
- plasmid DNA
- cytoplasm
- cell wall
- plasma membrane
- capsule
- bacterial flagellum
plasmid DNA
- small circular pieces of DNA able to replicate independently
prokaryotic vs eukaryotic
prokaryotic - small cells - unicellular - lack internal membrane - don't have nucleus - DNA single circular chromosome eukaryotic - large cells - multicellular - have membrane - have nucleus - DNA linear chromosome
endoplasmic reticulum
- intercellular and intercellular transport system
cytoplasm
fluid material where activities of the cell occur
plasma membrane
outermost barrier of the cell selectively allows some substances to pass through it
nucleolus
involved in the manufacture of proteins within the cell
nucleus
coordinates all the cells activities
ribosomes
site of protein synthesis
mitochondrion
site of cellular respiration
google apparatus
system of membrane that packages and stores substances before their release
temporary vacuole
a temporary storage sac
cell wall
provides extra support and protection to plant cells
large permanent vacuole
a fluid filled space that stores various materials
chloroplast
site of photosynthesis
