a2.2 cell structure

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EfficientCaribou2696

Cards (54)

a2.2.1 cell theory
all living things are composed of cells
the cell is the basic unit of life
cells come from preexisting cells
a2.2.1 deductive reasoning
using a general premise to form a specific conclusion
cell theory can be used to make predictions using deductive reasoning
a2.2.1 inductive reasoning
using specific observations to form a general conclusion
cell theory is an example of inductive reasoning
a2.2.2 - total magnification
total magnification = ocular x objective (e.g. 10X x 4X = 40X)
a2.2.2 magnification eq
magnification = size of image/actual size of specimen
a2.2.3 magnification definition
how much larger an object appears compared to its real size
a2.2.3 resolution definition
the smallest interval distinguishable by the microscope, which corresponds to the degree of detail visible in an image created by the instrument
a2.2.3 light microscope
can identify, observe and magnify objects by transmitting light through a string of lenses
a2.2.3 light microscope benefits
ease of use, less expensive, can observe both dead and living cells in colour, quick specimen preparation
a2.2.3 light microscope limitations
can only use wavelengths of visible light, limit of 1500X magnification, low resolving power
a2.2.3 electron microscope
uses beams of electrons to produce an enlarged image of a very small object, either by looking at the electrons bouncing off the surface of the sample or the electrons after they pass through the sample
a2.2.3 electron microscope benefits
short wavelength so higher resolution, show ultrastructure of cell, high magnification
a2.2.3 electron microscope limitations
expensive, can only observe dead cells, high voltage electric current required, specimen preparation takes a long time
a2.2.4 structures common to all cells
plasma membrane
cytoplasm
DNA
ribosomes
a2.2.4 plasma membrane
a phospholipid bilayer which separates the interior of the cell from its surroundings and controls the movement of molecules in and out of the cell
a2.2.4 cytoplasm
the cytoplasm contains cytosol, a gel-like substance made of water and dissolved solutes required to carry out metabolic processes
a2.2.4 DNA
contains genetic information needed for a cell to carry out all functions
a2.2.4 ribosomes
catalyse the synthesis of polypeptides during translation
prokaryotes - 70s ribosomes
eukaryotes - 80s ribosomes
a2.2.5 prokaryote cell structure
no nucleus
cell wall
plasma membrane
cytoplasm
70s ribosome
nucleoid DNA
some prokaryotes also have pili, a capsule and flagellum
a2.2.5 prokaryote cell wall
the cell wall, made of peptidoglycans, help maintain shape and support
a2.2.5 prokaryote DNA (nucleoid)
main DNA of the cell
not enclosed in a membrane, it is found freely in the cytoplasm
single loop not wrapped around proteins ("naked")
a2.2.5 prokaryote DNA (plasmid)
extra pieces of DNA not found in all prokaryotic cells
smaller than main nucleoid DNA and replicates independently
a2.2.5 prokaryote pili
enable cell to attach to surfaces, swap DNA with other cells and harpoon DNA in the environment
a2.2.5 prokaryote capsule
hydrated polysaccharide complex which surrounds the cell wall
helps cell keep from dehydrating and adhere to surfaces
a2.2.5 prokaryote flagella
filament attached to the plasma membrane by a basal body
molecular motor makes hook rotate, propelling cell
a2.2.6 eukaryote cell structure
plasma membrane
cytoplasm
80s ribosome
nucleus
mitochondria
chloroplast
endoplasmic reticulum (rough and smooth)
golgi apparatus
vesicles
vacuoles
lysosomes
cytoskeleton
a2.2.6 eukaryote nucleus
contains DNA (stores info for making proteins) and nucleolus (where ribosomes are made)
contains double nuclear membrane allowing cell to separate gene transcription and translation
DNA is tightly coiled around histone proteins
a2.2.6 eukaryote ribosomes
80s (larger than prokaryotes)
free floating in cytoplasm - synthesising polypeptides used within cell
bound - attached to RER synthesising polypeptides that are secreted from the cell
a2.2.6 eukaryote RER
rough endoplasmic reticulum
used in the synthesis of polypeptides
has bound ribosomes which synthesise the polypeptide and release it to the inside of the RER
continuous with nuclear envelope
a2.2.6 eukaryote SER
smooth endoplasmic reticulum
continuous with RER
no ribosomes
involved in lipid and cholesterol synthesis for the formation and repair of membranes
a2.2.6 golgi apparatus
modifies polypeptide chains into functional state
then packs proteins into vesicles
vesicles dispatched either within cell, to plasma membrane or outside the cell (via exocytosis)
a2.2.6 vesicles
membrane bound sacs that contain and transport materials within cells
transport and secretory vesicles
a2.2.6 transport vesicles
move molecules within the cell
a2.2.6 secretory vesicles
secrete molecules from within the cell via exocytosis
a2.2.6 lysosomes
small spherical organelles enclosed by a single membrane
contain digestion enzymes that work in oxygen-poor and lower pH areas
a2.2.6 mitochondria
responsible for respiration
evolved by endosymbiosis - surrounded by double membrane and contain own DNA
a2.2.6 chloroplast
adapted for photosynthesis (contains chlorophyll which captures light energy)
evolved by endosymbiosis
a2.2.6 vacuoles
used for water storage and to maintain turgor pressure against cell wall for plants to remain upright
a2.2.6 cytoskeleton
both prokaryotic and eukaryotic, not considered an organelle
helps cell maintain shape and organise cell organelles
a2.2.7 characteristics of paramecium which enable it to perform functions of life
heterotroph - eats smaller unicellular organisms for nutrition
move through its environment by beating cilia in different directions in response to changes in environment
contains enzymes that catalyse metabolic reactions
grows until it reaches maximum surface area to volume ratio
nucleus divides via mitosis before the cell reproduces asexually
waste from digestion are excreted through an anal pore
excess water within cell is collected into vacuoles to help maintain homeostasis