Eukaryotic Cell Structure Flashcards
State the Cell Theory.
1) Cell is the smallest unit of life in all organisms
2) All living organisms are composed of one or more cells
3) All cells arise only from pre-existing cells
State the structure to function of nucleus?
S1: Nuclear envelope perforated with nuclear pores
P1: facilitate entry and exit of macromolecules like mRNA
F1: in and out the nucleus
S2: Nucleolus comprises DNA carrying rRNA genes, rRNA and ribosomal proteins
P2: site
F2: of synthesis of rRNA & assembly of ribosomes
S3: Nucleoplasm contains euchromatin and heterochromatin
P3: Site
F3: for gene expression of transcriptionally-active euchromatin
State the structure to function of rough endoplasmic reticulum?
S1: extensive network of flattened membrane bound cisternae
P1: increased surface area for
F1: studding of more ribosomes, causing higher rate of protein synthesis
S2: 80S ribosomes attached to cytosolic face of rER
P2: allow rER to serve as a site of
F2: protein synthesis
S3: Continuous with the nuclear envelope, close proximity to the nucleus
P3: mRNA for the nucleus can be immediate used
F3: for protein synthesis at the rER
State the structure to function of smooth endoplasmic reticulum.
S1: network of interconnected membrane tubules
F1: Detoxification of drugs and toxins
F2: Synthesis and Transport of lipids
F3: Metabolism of Carbohydrates
F4: Storage of calcium ions
State the structure to function of Golgi Apparatus?
S1: Abundant stacks of flattened membrane-bound cisternae
P1: increased surface area
F1: for transport vesicle to fuse or secretory vesicle to bud off from GA
S2: Each golgi sac vary in thickness and molecular composition
P2: allow for
F2: different modifications for protein, lipids, to occur simultaneously
State the structure to function of lysosomes
S1: Membrane impermeable to H+
P1: maintain pH of 5
F1: which is acidic conditions for optimal enzyme reaction
S2: bound by single membrane
P2: compartmentalisation
F2: prevent spillage of enzymes into cytoplasm
S3: contain hydrolytic enzymes like proteases, nucleases
P3: digestion of worn out organelles
F3: autolysis and phagocytosis
State the structure to function of mitochondria
S1: Highly covulated inner membrane, known as cristae
P1: greater surface area for embedding more proteins
F1: for higher rate of oxidative phosphorylation, producing ATP faster
S2: Inner membrane impermeable to H+
P2: proton gradient can be generated
F2: for chemiosmosis in respiration to occur
State the structure to function of chloroplast
S1: Extensive thylakoid membrane stacked into a granum
P1: Increased surface area
F1: for embedding more proteins, for higher rate of light-dependent reactions
S2: Stroma houses great variety of enzymes like Rubisco (Ribulose Bisphosphate Carboxylase)
P2: the site for Calvin Cycle
F2: to yield G3P & sugars at the end
S3: Stroma contains circular DNA, 70S ribosomes
P3: allow expression of genes
F3: to synthesise chloroplast proteins
State the structure to function of centrioles
S1: positioned near the nucleus
P1: key to organising microtubules during cell division
F1: aid in separation of chromosomes
S2: each rod-like structure made up of 9 triplets of microtubules, arranged in a ring
P2: acts as microtubule organising centres
F2: assemble microtubules during cell division
State the structure to function of cell surface membrane
S1: phospholipid bilayer
P1: acts as a physical barrier
F1: between interior of the cell and extracellular environment
S2: embedded with protein channels, carriers and pumps
P2: regulation of
F2: large, hydrophilic, polar and charged molecules into and out of the cell
S3: Hydrophilic phosphate head faces outwards, hydrophobic lipid tails forms core of the membrane
P3: allow only
F3: small, non-polar molecules to pass through transient gaps of phospholipid bilayer due to hydrophobic core
What are the advantages of having a membrane?
1: Allow organelles to maintain unique internal environment like pH level for optimal rate of reaction and not be affected by cytosol or other organelle
2: Compartmentalisation: Allow incompatible processes to happen simultaneously
3: Increased membrane surface area for organelles like mito, chloroplast allow more enzyme complexes to be embedded, maximising rate of enzymatic reaction
State how polypeptide produced from ribosomes exit the cell?
1: Polypeptide synthesised by ribosomes enter the lumen of rER and undergo folding to form a specific 3D shape
2: followed by pinching off the rER in transport vesicles
3: Transport vesicle fuses with cis-face of GA
4: Polypeptides undergo chemical modification, is temporarily stored and then packaged into secretory vesicles, budding off at trans-face
5: Membrane of secretory vesicles fuses with the cell surface membrane, releasing the proteins out of the cell via exocytosis
