Bio exam Flashcards
Prokaryotic cells
prokaryotic cells are unicellular organisms that do not have a membrane-bound nucleus, mitochondria, or any membrane-bound organelles. there are two types of prokaryotes: archaea and bacteria
Eukaryotic cells
Eukaryotic cells have a nucleus and other organelles that are enclosed with membranes. Eukaryotic cells may be unicellular or multicellular. Animal, plants and fungi are all eukaryotic
Electron microscopy
Electron microscopy uses a bean of electrons to illuminate objects. electons ahve significantly smaller wavelengths compared to visvible light pronts so electron miscrospy can image objects on a much smaller scale, also providing. more dtail than light microscopy.
phospholiqid bilayer
describe the cell membrane as a two dimensionsl liwuid which restructs the diffusion of moslies across its lipid bilayer. components of the cellualr membrane include, portienns, cholestrol and carbohydrates.
How do cells coordinate wiuth their interal and external enviroemntsb
the plsama membrane which surround the sell is selectivley permable. meaning it allonly allows certain subsyances to move in and out. the mechanisms which are used to pass mayeirals through the cel membrane include: diffusion, osmosis, active transpsort. endocytosis and exocytosis
Diffusion
The movement of molecules from an arwa if high concentratyion to low concreaentation until equilibrum is reached. diffsuion is a passive gtransprt as it does NOT require energy input
Facilliated diffsuion
means mechainsims such as an. ion channel exists across the membrane to flow certain molecules through
Osmosis
passive movement of water across a membrane to equalise the concentrayion of solution of both side
Normal balanced water levels a cell is in a …. solution.
isotonic
Too much water the cell is in a ….. solution
hypotonic and may lyse (break down the mebrnae of a cell)
Too little water the cell is in a … solution
hypertonic
Active transport
movement of molecules across a membrane requiring an input of energy - often ATP
- pftern when molecules are to large to move across on their own or when trying to move across the concentraion gradient
endocytois and ecosytosis
endpcytsois type of active transport iused to bring external materials, such as proteins into the cytoplasm of the cell. it does this by engulfing them in part of the outermemrbane, forming a vescile inside of the cytosplasm.
Ecosytosis is the opossite
Surafce area to volume ratio
the larger a cell gets the smaller its surface area to violume area becomes smaller
Autotropjs
organsims which are able to producve tehir own food ethier using photosynthesis of chemosystemsis (using chemials such as sulfer)
they form the basis of the food chain
Heterotrophs
organisms whci are not able to synetheis their own food so they misty reply on the consumption of other organisms or external carbon molcules for their nutrtional carbon source.
Metabolism
the sum of all chemical processes which take place within an organsim
refers to all the nabolic (synthesis of molecules) and catebolic (breakdown of molcesules) processes that occur within a cell
chemical equation for photosynthesis
6C02 +6H20 + LIGHT –> C6H1206+6O2
Anerobic vs aerobic
aerobic meaning in the presence of oxygen and anaerobic meaning without oxygen
Arobic respirtaion equation
C6H12+6O2 –> 2CO2+6H2O+ ATP energy
Anerobic respiration in human and yeat cells
human: glucose –> lactid acid + energy
yeast( fermnentation): glucose –> ethonal + carbon dioxide + energy
Enzymes definition and composition
Highly specific biological cataylsys whocj omvcrease the rate of metabolic reactions by lowering the ‘activtion energy.’
Enzymes are made of amino acids which are bonded in a specidic lunear irder and then folde dto form proteins
What is the active site
the active site os an area of the enzyme which contains a specfifcx sequence of a mino acids with reactive side chains that can chemically intercat with a substance. the biomoleciles, called substrates bind ti the active site and undergo a chemical reaction
2 theories:
lock and key
induced fit (not perfectly shapped to accomidate the substarte but chnages shape to bind the substarte and act on it
an enzyme can become denatured
Multi vs unicellular
unicellular are on an organelle level
multicellular are on a cell, tussle and organ level
cell differentation
the processes why which a less soeculaised cell changes to a specilaised type of cell for example a blood stem cell differentiates into a red blood cell
cell specilisation
the specific funstion which a cell has, determined by their phuology and cillualr structures, for example red blood cells are speciliased with haemoglobin molecules to carry oxygen
processes of cell differentation and sepcilisation
stem cells are un-differentiated cells. when organisms begin development as embryos, all are cells are embyotic stem cells. as the embroui continues to grow and divide, these stems cells being to differinate, so that the cell beocme certain types of cells which preform specific functions. The changing. of a stem celll into a type of cell is differntaition and the final form they take is specialisation.
Tissue
A group pf cells which work together to perform a function for example a muscld cell work together in a muscle tissue to produce motion in the body
Muscle tissue: makes up musles
nervous tissue: makes up the nervous system (coordinate bodily fucntion by passing electrochemcial signals to detect and respond to external stimuli)
epitheallial tissue: coats surface of the body including digestive tract and skin
plant tissues
Mesophyll tissue
Xylem tissue
Meso: Made up of mesophyll cells, containing chloroplats to perform photosynthesis functions
Xylem: made up of tran=chieds, which are elongated and have a thick cell wall, specuaised for allowing water flow
Organ
a structure which is composed of a number of tissues which work together to perform a shared function
Level of structure
Organelle - cells - tissues - organs - system
Pressure-flow theory
nutruents are moved into the phloem by active tyransport at the source (photosynthesis cells)
water follows osmisis creating a pressure gradient
nutrients move passively down the phloem, following the pressure gradient
sugars are actively trasbported out of the phloem at the sink (cells which require glucose/nutrients)
Microscopic gas exchange in mammals
Alveoli: cluster sof air sacks which air flows into to form the bronchioles of the lungs
Microscopic gas exchange in plants
stomata are the structures for gas exchange in plants. furing gas exchnage the gaurd cells of the stomata nbeco,e swollen and turgud, opening the pore. oxygen will diffuse out of the stomata and co2 will diffuse into the stomata
Macroscopic gas exchange structures
mammals: lungs
fish: gills
insects: trancheae
transirpation cohesion tension theory
the mechanism by which water flows through the xylem of plants deu tio the combined effects of
transpirtaion (evaportaion of water through the stomata of plants)
cohesion (the water molecules are attracted to each other, so will move in a cohesive stream)
tension (water molecules are attracted to the surfaces which they touch)
