cell quiz 1.1-1.2 Flashcards
unicellular organisms
single celled, carry out all the functions of life independently
multicellular organisms
have specialized cells to carry out specific functions
organelles
specialized structures within the cell, carry out different functions, cannot survive alone
cells come from existing cells
cells multiple through division (mitosis-> identical diploid daughter cells, meiosis-> haploid gametes)
functions of life
nutrition
growth
response
excretion
metabolism
homeostasis
reproduction
smallest to largest
small molecule, virus, bacterium, animal cell, plant cell
plasma membrane is…
the surface of exchange for materials btwn the inside (oxygen, nutrients, water) and outside (co2, waste, products/proteins) of the cell
why does the surface area to volume ratio limit the size of a cell?
- as the cell gets larger –> requires more resources to be imported + exported –> large volume requires more exchange across the membrane
- as the cell gets larger –> SA to volume ratio gets smaller –> exchange processes become less efficient with increasing size
- by dividing to make smaller cells, exchange processes across the membranes can be kept high, shorter diffusion paths, more surfaces for reactions, easier removal of heat + waste
diffusion pathways are
shorter + more efficient with a larger SA to volume ratio bc molecules do not have to travel far to get in/out of cell
folded structures
maximize SA to volume ratio for exchange of materials
scanning electron microscopes
high-resolution 3D surface images
transmission electron microscopes
view of inside of cells and organisms
actual size =
measured length/magnification
magnification =
measured length/ actual size or drawing bar/scale bar
field of view at 4x, 10x, 40x
4 mm, 2 mm, 0.4 mm
calculating field of view
fov1 x magnification 1 = fov2 x magnification 2
importance of surface area to volume ration as a factor of limiting cell size
- small cells have larger ratio, ratio decreases as size increases
- SA/membrane must be large enough to absorb substances needed and excrete waste products
- need for materials is determined by cell volume
cells divide when they reach a certain size - diffusion
prokaryotes
before nucleus, evolutionary precursor to eukaryotes
flagella
propels cell
fimbriae/pilli
appendages that allow a bacterium to stick to a surface
cell wall
rigid structure that surrounds, supports, protects cell
plasma membrane
acts as a selective barrier, allowing oxygen, nutrients, wastes
ribosome
site of protein synthesis
nucleoid
contains genes that control the cell
binary fission
primary method of reproduction for prokaryotes, asexual reproduction, doesn’t increase variation in population
conjugation
prokaryotes exchange plasma DNA through pilli
evidence of endosymbiotic theory (evolution of eukaryotes from prokaryotes)
Membranes - some organelles have double membranes (outer membrane may be vesicular in origin)
Antibiotics - susceptible to antibiotics (indicates organelles have bacterial origins)
Division - reproduction occurs via fission-like process
DNA - has own DNA which is naked and circular (like prokaryotic DNA structure)
Ribosomes - 70S in size (identical to prokaryotic)
totipotent
can differentiate into any cell type
pluripotent
can differentiate into many types of cell
multipotent
can differentiate into a few closely related typed of cell
unipotent
can regenerate into a another accoi
stargardt’s disease
Early vision loss usually leading to blindness due to a gene mutation
Retinal pigment epithelial stem cells can be used to regenerate and support function of the eye’s light sensitive cells that have been damaged
prokaryotic vs eukaryotic
- DNA in ring form without protein | DNA with proteins (chromosomes/chromatin)
- DNA free in cytoplasm (nucleoid region) | DNA enclosed within a nuclear envelope (nucleus)
- no mitochondria | mitochondria
- 70S ribosomes | 80S ribosomes
- no membrane bound organelles | membrane bound organelles
types of eukaryotes
protista (unicellular, or multicellular with specialized tissue)
fungi
plantae
animalia
nucleus
- double membrane, continuos with ER
- contains DNA and proteins (genetic info), DNA wound around proteins organized into chromosomes
- pores allow mRNA + rRNA to pass through
- nucleolus makes ribosomes
ribosomes
no membrane bound, site of protein synthesis, made of rRNA + protein, soe atached to ER, some are free
proteins on bound ribosomes
secreted out of cell
proteins on free ribosomes
used inside cell
endoplasmic reticulum
smooth: no ribosomes, has enzymes embedded in the membrane, synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poisons, stored Ca++ in muscle cells
rough: ribosomes, synthesis of proteins and glycoproteins, make membrane proteins and phospholipids that make up its own membrane
golgi apparatus
- flattened membranous sacs
- proteins + phosphos modified
- products leave vesicles, these can go other places in the cell or to the membrane for secretion
- products from ER chemically tagged and sorted to go into the right places
lysosome
- membranous sac with digestive enzymes (hydrolytic)
- intracellular digestion of macromolecules
- recycling of damaged organelles called autophagy
mitochondria
cellular respiration
vacuoles
- hydrolytic enzymes
- plant, fungi, protista
- food vacuoles store food
- contractile vacuoles in protists control water and salts
- plants have central vacuole that gives internal support, stores organic molecules, pigments, poisons
chloroplast
photosynthesis
cell wall
plant cell
carbohydrate storage
animal - glycogen
plant - starch
chloroplasts
plant cells that photosynthesize
vacuole
animal - small if present at all
plant - large, fluid filled vacuoles
centrioles
animal cell - in a small centrosome ares
