Cell structure Flashcards
State 4 features found in both animal and plant cells
Plasma membrane
Nucleus
Cytoplasm
Mitochondria
State the features found only in either a plant cell or an animal cell (4)
> Centrioles (animal)
> Cell wall (plant)
> Large central vacuole (plant)
> Chloroplast (plant)
State the formula for magnification
magnification = observed image size / actual size
triangle:
. . I . .
.A . M .
Define magnification
The number of times larger an image of an object is than the actual size of the object.
Define resolution
The ability to distinguish details between two objects very close together
Convert nano meter to micrometer to millimeter
1,000,000 nm -> 1000 um
1000 um -> 1mm
or:
(1,000 nm -> 1 um
1 um -> 0.001 mm)
Distinguish between an electron microscope and a light microscope
Electron microscope: Used to see things smaller than 200 nm. Has better resolution than a light microscope
Light microscope: Used to see things bigger than 200 nm. Can pick up colours using colour dyes.
Distinguish between a TEM (transmission electron microscope) and a SEM (scanning electron microscope).
TEM (transmission electron microscope): electrons go through the specimen, forms 2D images and produces a higher resolution in comparison to a SEM
SEM (scanning electron microscope): Scans specimen, forms 3D images and produces a lower resolution in comparison to a TEM
State the role of the nucleus (3)
stores DNA
production of rRNA
production of RNA (rRNA , tRNA, mRNA)
Describe the structure of the nucleus (4)
> Nuclear envelope
Nuclear pores
Nucleolus
Chromatin
What form does an uncondensed and condensed DNA take?
uncondensed: chromatin, loose and unpacked -> before cell division,
condensed: chromosome, packed and dense -> during cell division
Which ribosomes can be found in the mitochondria and chloroplast?
70s ribosomes
Which ribosomes can be found in the cytoplasm of eukaryotic cells and prokaryotic cells?
(nucleus) Eukaryotic: 80s
(no nucleus) Prokaryotic: 70s
Which microscope can ribosomes be seen with?
electron microscopes
Which 2 key components are ribosomes made up of?
rRNA and (ribosomal) proteins
differentiate between rRNA , tRNA and mRNA
rRNA: A major component of ribosomes
tRNA: Brings amino acids to ribosomes (to synthesise proteins)
mRNA: Carries genetic instructions from the DNA to the rest of the cell (ribosomes)
Differentiate between the rough ER and the smooth ER by structure
The rough ER has membrane-bound ribosomes, giving it a rough appearance, while the membrane-bound ribosomes are absent in the smooth ER.
State the function of the rough ER
Protein synthesis, modification and folding
State the function of the smooth ER (5)
Lipid synthesis
Steroid synthesis
Carbohydrate metabolism
Detoxification
Storing calcium ions
Describe the structure of the golgi apparatus
made up of a series of stacked, membrane-bound sacs called cisternae and forming a lumen. It has a cis face (receiving side) and a trans face (shipping side).
State the functions of the golgi apparatus (5)
> Lysosome synthesis
> Glycoprotein synthesis (sugar + protein)
> Glycolipid synthesis (sugar + lipid)
> Synthesis of polysaccharides (formation of new cell wall in plant cells)
> modifying, sorting, and packaging various biomolecules
State the enzymes found in lysosomes (5)
> Hydrolases
> Proteases
> Lipaseases
> Nucleases
> Lysozymes
State the function of lysosomes (3)
> Endocytosis: Digests materials taken into the cell
> Exocytosis: The lysosome may be released from the cell for extracellular digestion
> Self digestion: Lysosome contents are released into the cytoplasm for self digestion
-Autophagy: digestion of organelles (unnecessary or damaged)
-Apoptosis: digestion of the cell (cell death)
Describe the structure of the mitochondria (6):
> Double membrane (envelope)
> Outermembrane
> Innermembrane
> Intermembrane
> Cristae
> Matrix
(70s ribosomes and circular DNA can be found within the matrix.)
State the function of the mitochondria (3)
> Carries out aerobic respiration
> Synthesis of ATP
> Storing calcium ions
What is the role of the Cristae?
increased surface area, allowing for more enzymes to attach, which in turn increases the synthesis of ATP
What makes up centrioles?
microtubules
Which monomer makes up protofilaments (by polymerization)?
Dimers (made up by alpha and beta tubulins)
______ Is the main component of the cytoskeleton
Microtubules
Describe the structure of the centriole
Long, rigid, hollow tubes made up of 9 microtubule triplets
(Found near the nucleus)
Where does the assembly and breakdown of microtubules take place?
MTOC (microtubule organizing center) / Centrosome
What are the 2 components of the centrosome?
The mother and daughter centrioles
What are the cilia and flagella made up of?
Centrioles and microtubules
Describe the structure of the cilia/flagella
Basal body (made up of centrioles)
Axoneme (arised from the basal body, made up of microtubules)
Describe the axoneme structure
9+2 formation of microtubules. (9 sets around, 2 in the center).
2 in the center: complete (13 protofilaments)
9 sets around, in each pair, 1 complete (A - 13), 1 incomplete (B - 10), complete one has dynein arms connected from the A microtubule to the B microtubule for movement.
Describe the chloroplast structure (3)
> Chloroplast envelope (double membrane)
> Outer membrane
> Inner membrane
- (Within the chloroplast):
> Thylakoids (forms grana when stacked)
> Stroma (fluid-like substance around the grana)
> Lipid droplet (in stroma)
> Starch grain (in stroma)
State where the light dependent and independent reaction takes place
Light dependent: Thylakoid membrane (chlorophyll)
Light independent Stroma
Explain the use of stroma
Contains starch grains, lipid droplets, circular DNA, 70s ribosomes, RNA, and enzymes
State the properties of the cell wall (4)
> Rigid
> Inelastic
> High tensile strength
> Freely permeable
What is the function/role of the cell wall? (5)
> Mechanical strength
> Prevent cell from bursting
> Helps determine shape
> Cells of the roots endodermis contain subserin
> Allows for apoplastic pathway
Explain what the apoplast is
A pathway for movement of substances between neighboring plant cell walls.
State difference of vacuoles in plants and animals
In animals: small, temporary and are typically phagocytic vacuoles
In plants: very large, and acts as lysosomes and storage.
State the function of vacuoles (5)
> Support (making it turgid)
> Lysosomal activites (contains hydrolases)
> Growth in size
> Storage (Calcium ions, waste product, etc.)
> Food reserves (Storing sucrose, mineral salts, protein storing)
