Cell structure Flashcards
what is a cell
the smallest possible unit of life made up of organelles
Prokaryote characteristcs
smaller, only unicellular, no nucleus and no membrane bound organelles, circular DNA,
eukaryote characteristics
larger, can be uni or multi celled, has a nuclues and membrane bound organelles, linear DNA
pro and euk cells examples
pro is bacteria
euk is plants, animals, protest, and fungi
why dont all cells within a multicellular organism look alike
some are specialized with different functions
what does it mean to be specialized
altered for a specific function
what does differentiaition mean
a process by which cells become specalized because some genes are expressed and some are turned off which dictates what proteins are made
what are some organelles present in both pro and euk
ribosomes
endoplasmic reticulum
chromosomes
cytoskeleton
what is the functional relationship among the components of the cytomembrane system
they work together and are involved in the synthesis of proteins/membrane
what are organells only found in euk
mitochondria,
rER/sER,
golgi apparatus
nucleus
rough endoplasmic reticulum function
to synthesise proteins that will be exported form the cell, contained within the vesicle, or embedded within the membrane
polysomes function
ribosomes linked together by mRNA and synthesize cytoplasmic proteins
function of free ribosomes
these are inactive
why cant animals do photosynthesis
because they dont have cholorplast/cholorphyll
what are some characteristics of the ancestral prok that allowed it to evolve into the first euk
there was a nuclues present, lots of folding of the cell membrane (ER present), increased size, evolved ability to enfulf without digestion
what is the endosymbiotic theory
a theory that the euk cells came from prokaryotes . because one smaller pro was engulfed by a larger one and they then formed a symbiotic relationship
what evidence supports the endosymbiotic theory
mitochondria has dna present, euk have a double membrane, euk have ribosomes that are smaller than in chloroplast and sim to pro, euk also duplicate similar to prok.
Microfilaments main structure
made up of strands of the protein actin and other proteins.
microfilaments main function
to drive cellular motion, like contraction
intermediate filaments structure
made up of fibrous proteins that are organized into tough, ropelike assemblages
intermediate filaments function
to help maintain cell shape, hold neighboring cells together, or make up the nuclear lamina
microtubules structure
long, hollow cycinders made up of many molecules of the protein tubulin
microtubules function
interactions between microtubules drive the movement of cells.
cytoskeleton structure
long proteins that interconnect
cytoskeleton function
maintain shape and movement (either the cell within their environment or organelles within the cytoplasm).
why dont prok need an extensive cytoskeleton
they dont have membrane bound organelles
the are really small and can just use diffusion
shape is maintained with a cell wall, not proteins.
