cell structure Flashcards
what is the main function of a nucleus?
controls the activity of a cell
how exactly does a nucleus control the activity in cells?
Makes DNA and RNA
what does the nuclear envelope consist of?
*including its functions
1-inner membrane
2- outer membrane which has ribosomes
3- nuclear pores to transport substances in and out of the nucleus
what is found in the rough endoplasmic reticulum and as a result what is the main function of RER?
ribosomes are found and it is a part of the site of protein synthesis
when proteins are made in the rough endoplasmic reticulum, what does the RER do to it?
proteins bud off from the RER in vesicles and are taken to the Golgi apparatus for processing
what is an important protein made by the rough endoplasmic reticulum?
lysosomes
what is the specific term for what is contained in lysosome and give 4 examples of them.
hydrolytic enzymes(lysozyme enzymes) 1- protease 2- nuclease 3-lipases 4-glucosidases
what are 3 main functions of lysosome
1- breakdown of old organelles 2- breakdown macromolecule 3-phagacytosis * bacterium in vacuole fuse with lysosome to from a vacuole of the bacterium and hydrolytic enzymes 4-autolysis
what does the smooth ER contain?
enzymes
what does the enzymes in the smooth ER do?
1- lipid synthesis *fatty acids to lipids 2- detoxification * enzymes convert harmful substances into water soluble ( lipid insoluble) 3- make steroids
1 example of a lipid and 2 examples of a steroid
lipid -cholesterol steroids *hormones - testosterone -estrogen
how many subunits are ribosomes made up of?
2 being a smaller and a larger unit
what is the main function of ribosome?
a site of protein synthesis
what are ribosome made up of?
R.RNA and protein
where is the R.RNA made ?
nucleolus
what 4 organelle can ribosomes be found at?
1- nucleus * outer membrane of nuclear envelope 2- chloroplast 3- cytoplasm 4- rough endoplasmic reticulum 5- mitochondria
what are the sizes of ribosome in the 4 main areas it can be found at?
bacterium,chloroplast and mitochondria =70S cytoplasm =80S *larger ribosomes
what do mitochondrion and chloroplast have their own of?
ribosomes and a circular DNA
what type of membranes do mitochondria’s have?
double bound membrane
what is the name of the mitochondrial inner membrane and its function
cristae
1-has compartments with different enzymes used in respiration cycle
2- where respiration occurs
What is the inner part of the cristae called and its function?
matrix ,where respiration takes place
what are 2 functions of the mitochondria?
1- aerobic respiration
2-lipid synthesis
what is the Golgi apparatus know as?
the packaging center
what is the function of the Golgi apparatus including the faces involved.
used to process and transport molecules such as proteins and lipids by the cis and trans face
what are molecules of the Golgi body transported via?
the Golgi vesicle
what are 2 main functions of the Golgi body?
1- make lysosomes
2- packing proteins and lipids
what type of layer is the cell membrane?
phospholipid Bilayer
what is found on the phospholipid bilayer?
protein molecules
protein channel
cholesterol
what are 3 functions of the cell membrane?
1- regulates what enters and leaves the cell
2-acts as a barrier protecting organelles from its outer environment
3- communication via the protein receptors which receives signals by eg;hormones
what is the function of the cilia?
create beating movement
what is the structure and function of microvilli?
finger like projections which increase surface area
what are 4 structures found in plant cells but not in animal cell?
1- chloroplast
2-tonoplast
3- cell wall
4- large vacuole
what is cell wall made up of in plants and fungi?
in plants=cellulose
in fungi=chitin
what is the main function of a cell wall? and how exactly does it do its function?
supports the cell by
a- giving its structure
b- preventing a change in the cells shape
what is the name of part of the vacuole? and what does it contain
cell sap which contains sugar and salts
what are 3 functions of the vacuole?
1- maintains the cell pressure by pushing cytoplasm against cell wall
2- isolates harmful substances from the rest of plant cell by storing it
3- stores salts and sugar
what is the “membrane” surrounding the vacuole besides cell membrane
tonoplast
what is the function of the tonoplast?
creates a barrier between the contents of the vacuole and the cytoplasm
what does the chloroplast contain, highlighted in the syllabus?
1- small circular DNA
2- ribosomes
what is the name of the stacked up structures in chloroplast and what is it made up of ?
granum made up of thylakoid membrane
what are the stacked up structure in chloroplast connected by?
thinner thylakoid membrane named lamella
what is the empty space of chloroplast filled up with?
stroma
what is the main function of the chloroplast?
light and non light dependent photosynthesis
what is the plasmodesmata
structure which connects 2 adjacent cells
what are 3 functions of the plasmodesmata?
1- allows communication between cells
2- allows exchange of substances between cells
* sucrose
*water
*ions
*amino acid
3- allows exchange between cells without having to pass through the cell membrane or cell wall
explain the structure of microtubules
1-proteins known as alpha-tubulin and beta-tubulin pair and are called dimer.
2-many dimers join to from a protofilament
3-13 protofilament makes up a microtubule
what is a feature of microtubule which relates to its function?
dimers are able to be added or removed to make the microtubule longer or shorter
explain 3 functions of the microtubule
1-mitosis
: used in mitosis in anaphase where the microtubules
become shorter to allow the chromosomes to form
chromatids2- transport in neurons
: the microtubules make a pathway from the cell body
to the synaptic terminal where with the help of
protein substances are moved.
3- make cilia/flagella
: the microtubules are arranged in a specific way to
make the cilia/flagella
3 examples of substances which can be transported by microtubules in nerve cells
- protein
- lipids
- synaptic vesicle containing neurotransmitter
- organelles such as mitochondria
describe the structure of cilia
1- has 2 unattached microtube in the middle
2- 9 groups of paired microtubules form a circle
3-the complete microtubule has 13 protofilament
4- the incomplete microtubule has 10 protofilament
5- the complete microtube contains arms made up of dynein protein
describe the structure of centrioles
- made up of microtubules where 3 microtubules{ 1 complete and 2 partial} form a group.
- a total of 9 groups are found to make up 27 microtubules.
- these 27 microtubules make up 1 centriole
describe a function of microtubules
used during mitosis where the centrioles help to anchor the microtubule to align the chromosomes into the center of the cell during the metaphase
what are general structures found in plant cells but not animal cell?
large vacuole chloroplast tonoplast cell wall plasmodesmata
what are general structures found in animal cell but not plant cell?
centrioles, cilia, flagella, microvillus, microtubules
what is the stroma and what does it contain
the jelly like substance in chloroplast which contains enzymes
what are 3 plastids?
chloroplast
leucoplast
chromoplast
outline the 3 plastids
chloroplast- general stuff
chromoplast- contains carotenoid pigments which makes red ,yellow and orange pigments
leucoplast divide into 3
proteinoplast: in seeds, to store proteins
amyloplast: in seeds and roots, to store starch
eliaoplast: found in seeds, to store lipids
describe the peroxisome
a single membraned organelle containing enzymes used to oxidize and remove toxic waste in cells eg: breakdown of hydrogen peroxide into oxygen and water
what are the 3 composition of the cytoskeleton?
intermediate filaments
microtubule
microfilaments
outline the 3 compositions of the cytoskeleton
intermediate filaments -structural proteins
microtubule- forms a transport system for organelles
microfilament- made up of threads of actin and used in muscle contraction and movement
what are plastids?
plastids are self-reproducing double membraned organelles found in plants
describe how a microtubule is formed
- alpha tubulin and beta tubulin form dimers
- the dimers join end to end to form 1 protofilament
- 13 of these protofilaments arrange themselves in a ring to form a microtubule
what is the centrosome?
an area where centrioles can be found 90 degrees to each other
what are the differences and similarities of basal body and centrioles
similarity
-both have a triplet structure of 9+0
differences
- centrioles at the centrosome is a microtubule organizing center [involved in replication]
- basal bodies are microtubule organizing center for cilia and flagella
what are the 2 parts which make up a cillia/flagella?
1-basal body triplet to organize the microtubule for cilia
2- 9+2 structure of a cilia
