cell structure of an animal cell(eukaryotic)
nucleus
lysosome
mitochondria
small vacuole
ribosome
smooth ER
rough ER
peroxisome
golgi apparatus
plasma membrane
plasma membrane
selectively permeable, separates inside and outside of cell
Nucleus
Contains genetic info(DNA cannot leave the cell so it gets copied to RNA)
Lysosome
digestive organelle, has enzymes(hydrolytic/digestive enzymes) that hydrolyze(break down) macromolecules, helps with apoptosis
-lysosomes can fuse with food vacuoles to help digest food
mitochondria
ATP production
small vacuole
stores/transport material/waste
Ribosomes
free ribosomes(in the cytoplasm): make proteins for use inside the cell(intracellular use)
bound ribosomes(to the rough ER): ribosomes that make proteins to be transported outside the cell
Smooth ER
lipid synthesis, carb metabolism, detoxifying, Ca+ storage
Peroxisome
metabolic functions, makes H202 to break down fatty acids
Golgi apparatus
synthesis, modify, sort and transport/secrete cell products
Rough ER
contains bound ribosomes that make proteins to be released outside of the cell
Endomembrane system
-these organelles working together to produce, modify, package, and transport materials out of the cell
nucleus(DNA→mRNA) —> Rough ER(proteins) —> Golgi(modify, sort, transport proteins) —> vesicles go to cell membrane to release material(proteins transported to cell membrane and released)
Structures in plant cells but NOT animal cells
-large central vacuole: storage, water & other molecules
-chloroplast: photosynthesis
-cell wall: made of cellulose, maintains shape, protection
Cell size and surface area to volume ratio
Smaller cells = LARGER surface area to volume ratio(more efficient at getting materials in and out)
Larger cells = SMALLER SA:V ratio (Less efficient at transporting materials in and out)
Mitochondria SA:V
the highly folded inner membrane = more SA to produce ATP(where the ETC is located)
Intestinal cells
highly folded membranes = more surface area for nutrient absorption
The cell membrane(phospholipid bilayer)
phosphate group(head) = polar, hydrophilic
fatty acid tails = nonpolar, hydrophobic
selectively permeable
fluid mosaic
What can passively go through/diffuse the cell membrane?
nonpolar, small molecules(N2, CO2, O2)
steroid hormones(lipids, small, nonpolar)
H2O(polar but very small) — osmosis
What cannot passively go through/diffuse through the cell membrane?
ions(charged) - NA+, K+
polar substances
very large substances
Fluid mosaic model
The cell membrane is modeled as a “fluid mosaic”. It’s called a mosaic because it contains MANY other components such as proteins, cholesterol, glycolipids, etc. that are peppered throughout. It’s “fluid” as those components are not locked in place but can move around.
Passive transport
NO energy input(NO ATP)
High conc. —> Low conc.
goes down the conc. gradient
osmosis
facilitated diffusion
aquaporins
simple diffusion
Active transport
energy input(ATP) required
Low conc. —> High conc.
goes against the conc. gradient
endocytosis
exocytosis
sodium potassium pump
Osmosis
passive transport
H2O moves across membrane from high H2O conc. to low H2O conc.
H2O moves from low to high solute conc.
Movement of H2O across aquaporins
passive transport
pore in the cell membrane that allows large amounts of water through
simple diffusion
molecules move across membrane from high to low conc.
passive transport
facilitated diffusion
involves use of carrier protein or protein channel
passive transport
sodium(Na+) potassium (K+) pump
-transporting ions
requires ATP - active transport
endocytosis
taking materials into the cell
active transport
exocytosis
getting materials out of the cell
active transport
Water potential
H2O flows from where there is high ψ to low ψ
cell compartmentalization
eukaryotic cells are compartmentalized - have many different compartments or “cell parts” that each do a different function to help the cell work as a whole
prokaryotic cell structure
no nucleus
free DNA
cell wall
ribosomes
cytoplasm
flagella(some)
Endosymbiotic theory
explains the evolutionary origin of eukaryotic cells from prokaryotic cells - how they evolved from free-living prokaryotes
-symbiotic relationship in which the smaller “cells”(organelles) have a place to live + they make food or ATP for the larger “cell”(host)
What is the evidence for endosymbiotic theory?
-mitochondria and chloroplasts have their own naked and circular DNA like prokaryotes
-mitochondria and chloroplasts have double membranes
-mito. and chloro. have their own ribosomes similar to prokaryotic cells
-mito. and chloro. do fission-like division