Studied by 7 peoplecells
the basic unit of all organisms
two basic type of cells
prokaryotes and eukaryotes
what are the four common traits of eukaroytes and prokaryotes cells
surrounded by a plasma membrane
contain a semifluid substance called cytoplasm
contain structure called chromosomes DNA
contain ribosomes
what is the difference between a eukaryote cell and a prokaryote cell in terms of size
eukaryotic cells are larger than prokaryotic cells
what is the difference between a eukaryote cell and a prokaryote cell in terms of organelles
eukaryotic cells contain organelles inside of them; prokaryote cells do not
this includes the nucleus
what is the difference between a eukaryote cell and a prokaryote cell in terms of how quantity of cells contained in the organism
eukaryotes are multi-cellular organisms while prokaryotes are single cellular organisms
what is the difference between a eukaryote cell and a prokaryote cell in terms of chromosomes
Eukaryote chromosomes are contained within the nucleus prokaryote chromosomes do not
what is the difference between a eukaryote cell and a prokaryote cell in terms of the number of chromosomes
eukaryote chromosomes vary in number from organism to organism while prokaryotes have a single circular chromosome
surface area
determines the amount of substances the cell can take in and the amount of waste it can release
volume
determines the amount of chemical activity it can carry out
what is the ratio of surface area to volume and why?
surface area is larger than volume
allows more materials to move in/out of the cell so chemical reactions can occur
organelles
specialized internal cell structures that carry out specific cell functions
what type of cell processes do organelles carry out?
essential cell processes like protein synthesis, energy transformation, digestion of food, excretion of wastes, and cell division
protists
first eukaryotic cells
single-celled eukaryotes
they can range from protozoans to algae
what eukaryotes are multicellular
fungi, plants, animals
what does the nucleus contain
contains the DNA
what does DNA do
stores information used to make proteins for cell growth, function and reproduction
the manager
ribosomes
organelles that help manufacture proteins
what are ribosomes made of
RNA and protein
(not bound by a membrane)
where is the site of ribosome production
nucleolus
what leaves the nucleus through the nuclear pores?
ribosomes
what structure is DNA packed into
chromosomes
how do cells become specialized
turning on, or expressing certain genes in DNA
endomembrane system
made up of organelles that make protein, process them, and ship them to where they are needed, inside or outside of the cell
what organelles are included in the endomembrane system
nucleus
rough/smooth ER
golgi apparatus
lysosomes
endoplasmic reticulum (ER)
a membrane of folded sacs and interconnected channels that serves as the site of protein and lipid synthesis
rough ER
ribosomes are attached to it’s membrane
the attached ribosomes will synthesize proteins
smooth ER
does not have ribosomes on its surface
makes lipids, detoxifies the cells, and stores calcium ions
how does the golgi apparatus and the ER work together?
the golgi receives the transported vesicles that bud off from the ER and contains proteins
golgi apparatus
takes the substance from the ER (proteins) and modifies them chemically in order to mark them and sort them into different batches depending on their destination
the finished product will either move to the lysosomes, inserted into the plasma membrane, or dumped out of the cell
lysosomes
contain hydrolytic enzymes used to breakdown other substances
used to digest excess or worn-out organelles, food particles, and engulf viruses or bacteria
peroxisomes
special type of lysosomes
contains an enzyme which produces hydrogen peroxide and breaks it down
plasma membrane
phospholipid bilayer with proteins and other molecules interspersed throughout
three main functions of the plasma membrane
selective permeability
protection
structural support
phospholipid
amphiphilic having both hydrophobic and hydrophilic regions
contains a hydrophilic head and a hydrophobic tail (fatty acid)
why do phospholipids form a bilayer when placed in water?
to protect the hydrophobic tails from the water and then the hydrophillic heads can interact with the water on the inside and outside of the cell
passive transport
movement of substances from an area of high concentration to an area of low concentration without the requirement an energy input
active transport
the movement of substances from an area of low concentration to an area of high concentration and requires an input of energy
exocytosis
used to excrete a large molecule from the cell
the vesicle that encloses the proteins fuse with the plasma membrane and the vesicle then opens up and spills their contents outside of the cell
endocytosis
the cell takes in macromolecules or other particles by forming vesicle or vacuoles from its plasma membrane
chloroplasts
reside in plant cells and some protists and convert solar radiation into energy stored through photosynthesis
mitochondria
resides in all eukaryotic cells and converts chemical energy from glucose into ATP through cellular respiration
what makes mitochondria and chloroplast different from other eukaryotic organelles
they have their own DNA, their own ribosomes, and have a double cell membrane
Endosymbiotic Theory
the mitochondria and chloroplast were once prokaryotes that got engulfed by another prokaryote
they were both considered bacterias
when they got eaten by another prokaryote they got dragged by one prokaryote’s cell membrane around theirs making the double membrane and allowed the new eukaryote to make their own ATP/be able to do photosynthesis to make its own food
evolution of eukaryotes
what is the evidence of endosymbiotic theory
the mitochondria and chloroplasts can arise only from preexisting mitochondria and chloroplasts and cannot be formed in a cell that lacks them
they both have their own DNA and resembles the DNA of bacteria or prokaryotes (single circular DNA)
mitochondria and chloroplasts have their own ribosomes which closely resembles bacteria ribosomes than eukaryote’s ribosomes
Mitochondrial Eve
DNA is passed through from mother to child and you inherit your mitochondria from your mother only
the egg contains our mothers organelles and only dad’s sperm contains the chromosomes
mitochondrial DNA is a way to trace maternal heritage through a family or through a species and we can trace all humans back to her (eve) through mitochondrial DNA
chloroplasts
organelles convert solar energy to chemical energy through photosynthesis
three major compartments of chloroplasts
thylakoids
stroma
intermembrane space
two major compartments of the mitocondria
matrix
intermembrane space
vacuoles
membranous sacs which come in different shapes/sizes and have a variety of functions
central vacules
in plants store water which gives their strength and rigidity
stores vital chemicals, pigments, and waste products
full central vaculoes
take over the cytoplasm and push the organelles to the side
what happens when plants do not get enough water
the vacuoles are not full and the cytoplasm is pulled away from the wall, the plant wilts, limps, and droops
contractile vacuoles
found in certain single-celled protists
acts as pumps to expel excess water from the cell and keeps the cell from exploding
cytoskeleton
a network of fibers within the cytoplasm
provides structural support and are involved in various types of cell movement and motility
cell wall
an outer layer besides the plasma membrane
what are cell walls made out of
cellulose
fungal: chitin
cell junctions
allows cells to communicate and pass substances to one another
how do plant cell junctions connect
plasmodesmata
plasmodesmata (plural)
tight junctions
bind cells together into leakproof sheets
adhering junctions (desmosomes)
fasten cells together into strong sheets and are somewhat leakproof
gap junctions
allow substances to flow from cell to cell
what do plant cells have that animal cells do not have
cell wall, chloroplasts, vacuoles
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