enzymes, cells, membranes Flashcards
uninhabitable conditions of early earth
- very hot due to volcanism and heat bc c02 and c04 trapped in much high concentrations than today
- no ozone, which means no absorbing UV light which is harmful
- very little oxygen and the oxygen would react with iron minerals from volcanism to form iron oxides
- very little water since due to heat water would boil + evaporate and also not enough gravitational force for water to stay on earth
abiogenesis
- hypothesis: living organisms evolved from non-living matter
- cells are very complex structures, so this is not true
- Pasteur’s experiment
- abiogenesis happens in many stages, the first is prebiotic synthesis of small organic molecules from inorganic compounds.
-Prebiotic synthesis can happen in different locations on earth under right conditions (Miller Urey) - Next stage is small organic molecules joining together to form large molecules such as amino acids, fatty acids, lipids, carbohydrates, nucleic acids
- Next is the formation of small vesicles of amphipathic molecules such as fatty acids and phospholipids
- These vesicles are called protocells which form compartments. They are not true cells yet
- Has a barrier in the form of a membrane to separate the compartment of protocells from outside environment
amphipathic
- both hydrophobic and hydrophilic
LUCA (next stage of abiogenesis)
- last common universal ancestor
- strongest evidence of LUCA: the universality of the genetic code
- with rare exceptions, we all use the same genetic code
domain bacteria
“normal bacteria”
- prokaryote
- no organelles
domain archaea
extremophile bacteria
- extreme conditions
- prokaryote
- no organelles
domain eukarya
plants, fungi, animals
- has organelles
order of events of early life
- prokaryotes
- evolution of photosynthesis which released oxygen as waste (went from almost no oxygen to 21% oxygen)
- eukaryotes
atypical eukaryote cells
red blood cells
- no nucleus
skeletal muscles
- multiple nuclei
- long and large
giant marine algae
- some are large and unicellular
aseptate fungi
- no clear division between cells
sieve tubes
- plant cells with only cytoplasm
IAM triangle
- I = image size (using a ruler)
- A = actual size
- Magnification
mm –> um = x 1000
um –> mm = / 1000
nm –> um = / 1000
microscopes
- light microscopes are 400X-1000X (400x is sharper). Some better ones go to 2000X
- if needed higher magnifications you need electron microscopes (could go to 1,000,000X)
- Disadvantage is that anything living will die due to beams of electrons. Also images are always b&w but artificial color can be added
advancements in techniques (adding color)
Fluorescent staining
- fluorescent dye makes structures visible when “excited” by certain wavelengths of light
- can help make 3D shapes more visible
Immunofluorescence
- fluorescent dyes attach to antibodies which then are attached to antigens on a structure to make it visible by fluorescence
- antibodies are made just to be attached to the desired antigen
freeze-fracture
- cells in a solution are frozen then broken (fractured), coated, then viewed under electron microscopes to see the 3D view of surfaces and cell interiors
cryogenic electron microscopy (cyro-EM)
- particles are frozen under very low temperatures then multiple electron microscope images are collected. Then computer takes the photos and reconstruct the shape then render and colorize in 3D
prokaryotic cells
- bacteria is prokaryotic
- all prokaryotic cells have: cell wall, cell membrane, 70S ribosomes, cytoplasm, flagella, naked DNA
eukaryotic cells
- draw everything
functions + draw smooth endoplasmic reticulum
- function is to synthesize new lipids like cholesterol and phospholipids
- no ribosomes unlike RER
golgi apparatus
- flattened sacs of membranes
- proteins received from the ER are processed and repackaged for secretion
- wifi looking
- the bubbles are vesicles
lysosome
- a vesicle containing digestive enzymes
- digest food particles and damaged cell parts
vacuole + flagella
store water, sugars, amino acids, other molecules
gives cells mobility
order of smallest to biggest (size)
- My Crazy Mom Visits Bieber Outside Concerts
- molecules, cell membrane, virus, bacteria, organelles, cells
surface area
- how much material can enter a cell at once
- bigger surface area = more material
membrane diagram
- draw everything w labels
cholesterol
- affects membrane fluidity at diff temps
- decreases membrane fluidity at high temps
- increases membrane fluidity at low temps
movement through a membrane diagram
- draw everything
diffusion
- movement of molecules from high to low concentration
- requires no energy
- draw diagram
osmosis
-the movement of water molecules from a region of high water concentration through a semi-permeable membrane to a region of low water concentration
semi-permeable
- cell membrane that allow small molecules such as oxygen, water, carbon dioxide, ammonia, glucose, amino acids, etc to pass through
- will not allow large molecules such as sucrose, starch, protein, etc to pass through
substitutes for enzymes
- ribozymes
facilitated diffusion
- involves the use of proteins to facilitate the movement of molecules across the membrane.
- In some cases, molecules pass through channels within the protein
collision
- violent coming together of two or more moving objects against each other
collision theory
- explains why different reactions occur at different rates
- claims chemical reaction only happens between particles when they collide w each other
isotonic
- same concentration on both sides of membrane
- draw animal and plant cell diagram
hypertonic
- the more concentrated solution
- draw animal and plant cell diagram
hypotonic
- the less concentrated solution
- draw animal and plant cell diagram
active transport
- a type of transport where substances move against a concentration gradient in the opposite direction to diffusion
- low concentration to high concentration
- needs energy and protein pump to work (found in a membrane)
phagocytosis
- living cells called phagocytes ingest bacteria and other material
- large food particles that can’t fit through membrane are ingested by phagocytes
passive transport
- doesn’t require energy, easy for water and oxygen to get into cells
- simple diffusion
enzyme definition
- a biological catalyst
- allows reactions to take place more easily but not get affected by the reaction itself
substrate enzyme —> product
- a protein made up of many amino acids in a very long chain
- identity where the active site is
catalyst
- works by lowering activation energy of the reaction by providing a structure to hold the substance(s) in a place called the active site
pores
- nuclear pores
- allow RNA to go to ribomes to give information
denaturation
- when the bonds in the enzyme breaks permanently and the enzyme loses its shape
- enzyme stops working
cellular metabolism
- all chemical reactions that occur within a cell
anabolism
- reactions that join molecules together to build new ones
catabolism
- reactions that break molecules apart
- destroys things
- think “catastrophe”
homeostasis
- a self-regulating process by which a living organism can maintain internal stability while adjusting to changing external conditions.
the enzyme diagram
- draw
inhibition
- to inhibit means to hold in or back
