cells Flashcards
what does the nucleus do?
contains DNA which codes for protein synthesis
what does the nucleolus in the nucleus do?
synthesis of rRNA and ribosomes
what does the nuclear pore in the nucleus do?
allows the transport of mRNA out
what does the nuclear envelope in the nucleus do?
separates DNA from cytoplasm
what does the cell membrane do?
regulates the transport of materials entering and exiting the cell
what does the cytoplasm do?
site of cellular reactions
what does mitochondrion do?
site of aerobic respiration
which synthesis ATP
what is the structure of mitochondrion?
interior called matrix (contains enzymes)
inner membrane called crista
double membrane
rod shaped
contains DNA and ribosomes
what do rough endoplasmic reticulums do (RER)?
transports proteins which are synthesised by ribosomes attached
what is the structure of rough endoplasmic reticulums?
system of flattened sacs
has RIBOSOMES attached
what do smooth endoplasmic reticulums do (SER)?
synthesis and transport of lipids
what is the structure of smooth endoplasmic reticulums?
system of flattened sacs
NO ribosomes attached
what does the golgi body do?
chemically modifies and packages proteins for secretion out of cell
produces glycoproteins
produces lysosomes
what are centrioles?
two hollow cylinders positioned at right angles
what do centrioles do?
used in spindle formation in cell division
what do ribosomes do?
protein synthesis
what is the structure of ribosomes?
can be free or attached (RER)
2 subunits made from RNA and protein
what are lysosomes?
small vacuoles
formed when small portions of the golgi body are pinched off
what do lysosomes do?
contain digestive enzymes then releases to destroy harmful substances
what do vacuoles do in animals?
act as a control vacuole to maintain osmotic pressure
what do vacuoles do in plants?
storage of ions and organic molecules
LARGE MEMBRANE
what do vesicles do?
small structures within a cell
consists of fluid enclosed by a lipid bilayer
involved in transport
what do chloroplasts do?
site of photosynthesis
what is the structure of chloroplasts?
double membrane
stoma fluid
lipids
ribosomes
circular DNA
starch granules
thylakoids
what does a cellulose cell wall do?
provides strength and support for cell
freely permeable to water
what is the structure of a cellulose cell wall?
primary well
three layers of secondary wall
made of cellulose microfibrils in a polysaccharide matrix
what is a plasmodesmata?
narrow thread of cytoplasm that passes through the cell walls of adjacent plant cells
what does a plasmodesmata do?
exchanges large organic materials via cytoplasmic screening
allows communication between adjacent cells
how many smu in 1mm?
100smu
how many μm in 1mm?
1000μm
how does protein production in a cell occur?
nucleus DNA codes for sequence if amino acids into polypeptide chain
mRNA copies DNA by transcription through nuclear pore to cytoplasm
nucleolus synthesis rRNA (part of ribosomes)
ribosomes carry out protein synthesis
RER transports protein to golgi body in transport vesicles
golgi body modifies and packages protein into secretory vesicle
vesicle migrates to plasma membrane
protein fuses with membrane and is released by exocytosis
what is the structure of a prokaryotic cell?
no nucleus
genetic material is in nucleoid and plasmids
no membrane bound organelles
smaller ribosomes
some have slime capsule
what are the size of ribosomes in prokaryotes?
70S
what is the cell wall in a prokaryote made of?
peptidoglycan
what does a prokaryote contain?
ribosomes
plasmids and nucleoid
pilus/pili
mesosome
slime capsule
flagellum
what is a mesosome in a prokaryote?
infolding of cell membrane
what is in a virus?
small piece of RNA
reverse transcriptase enzyme
capside protein coat
what is the function of a plasma cell membrane?
separates cell from the environment
regulates transport
receptor site and recognition
what is in a plasma cell membrane?
extrinsic and intrinsic proteins
glycoprotein
glycolipid
cholesterol
phospholipid bilayer
what do the extrinsic proteins do in a plasma cell membrane?
structural support
recognition site to identify cells
receptor site
what do intrinsic proteins do in a plasma cell membrane?
structural support
channel/carrier protein
what does a channel protein do in a plasma cell membrane?
allows water and charged ions through (small polar molecules)
what does a channel protein contain?
a hydrophilic pore
what do carrier proteins do in a plasma cell membrane?
allows glucose and amino acids through by passive transport
(BIGGER SPACE THAN CARRIER)
what are glycoproteins?
carbohydrate + protein
what are glycolipids?
carbohydrate + lipid
what is glycocalyx in a plasma cell membrane?
layer of carbohydrates around the membrane
what do phospholipids contain?
hydrophilic phosphate head which interacts well with fluid outside cell
hydrophobic tails that do not interact well with fluid
what is the plasma cell membrane a barrier to?
larger polar molecules
water-soluble molecules
ions
what is the plasma cell membrane permeable to?
lipid-soluble molecules
non-polar molecules
very small polar molecules
what happens when you increase the temperature of the plasma cell membrane?
increases kinetic energy
increases vibrations
increases permeability
who found the plasma cell membrane?
Singer and Nicholson
what is the name of the plasma cell membrane model?
fluid-mosaic model
what part is the fluid bit of the fluid-mosaic model?
phospholipids and proteins
what part is the mosaic bit of the fluid-mosaic model?
proteins scattered within phospholipids
what are tissues?
group or layers of similar cells with the same function
what does epithelial tissue do?
lines space and hollow organs within body
protects cells underneath
secretes and absorbs substance
excretes waste products
what is the structure of epithelial tissue?
cells fit tightly together (no gaps)
one side exposed one side sit on basement membrane
what are the types of epithelial tissue?
squamous
cuboidal
columnar/ciliated
glandular
what do squamous tissues look like?
thin and smooth cells
what do squamous tissues do?
line tissues with smooth lining to reduce friction
thin layer of cells for gas exchange
where are squamous tissues found?
alveoli
blood vessels
what do cuboidal tissues look like?
box-shaped
prominent nucleus
what do cuboidal tissues do?
secretion and reabsorption
where are cuboidal tissues found?
kidney tubules
glandular ducts
what do columnar/ciliated tissues look like?
column shaped
can have cilia
what do columnar/ciliated tissues do?
ciliated cell walls waft dirt/dust out of air passages
microvilli increase surface area for absorption
what do glandular tissues look like?
gland shape
what do glandular tissues do?
secrete enzymes, hormones, salvia, mucus
where are glandular tissues found?
glands
pancreas
what do connective tissues do?
connect other tissues together
what do connective tissues contain?
collagen (apart from blood)
can contain fibroblasts
what can muscle tissues do?
shorten their length
contains proteins which slide past each other
what are the three types of muscle tissue?
striated (skeletal)
smooth
cardiac
what causes the striations (stripes) in striated muscles?
caused by overlapping protein molecules
what do striated muscles do?
skeletal movement
move bones
maintain posture and body position
support soft tissues
where are striated muscles found?
attached to bones by tendons
where are smooth muscles found?
walls of hollow organs
what do smooth muscles do?
work automatically
housekeeping of body functions
what is the structure of smooth muscles?
unstriated
what is the structure of cardiac muscles?
fibres are striated and branched
attached to adjoining fibres by thick plasma membranes
what do cardiac muscles do?
rhythmic contraction to pump blood through the heart
what does the cristae in mitochondrion do?
increases surface area for ATP synthesis
what is in mitochondrion?
inner membrane
outer membrane
matrix
cristae
intermembrane space
why do mitochondrion sometimes look different?
they have been cut in a different plane
