lecture 6 - cell structure +function

Question 1

phospholipid structure

Answer 1

Hydrophilic polar (phosphate) heads, hydrophobic lipid (fatty acid) tails

Question 1

Membrane protein functions

Answer 1

Transport (general or selective), cell-cell recognition, signal transduction, join cells together, enzymatic activity, attachment to cytoskeleton + ECM

Question 2

Integral proteins

Answer 2

Embedded in membrane, can be partial or full across membrane (transmembrane)

Question 3

Peripheral proteins

Answer 3

NOT embedded in membrane jut associated to it.

Question 4

Nucleus functions

Answer 4

Molecule segregation for temporal and spatial control of cell functions, mRNA production (in nucleolus), stores/protects DNA, pores regulate movement of proteins/mRNA in/out

Question 5

Chromatin structure

Answer 5

DNA wrapped around 8 histones makes a nucleosome. Lots of nucleosomes together makes chromatin. Chromatin folds into chromosomes.

Question 6

Ribosome structure

Answer 6

Small + large subunits made of ribosomal rna (rRNA) in complex with many proteins. Subunits assembled in nucleolus.

Question 7

ER structure

Answer 7

Cisternae (network of tubes/sacs) with lumen, ribosomes, transitional + rough + smooth ER

Question 8

Rough ER function

Answer 8

produce membrane proteins, secreted proteins, organelle proteins. proteins enter rough lumen for folding.

Question 9

Smooth ER function

Answer 9

Produces lipids (steroids + phospholipids), stores cell specific proteins/enzymes

Question 10

Golgi body structure

Answer 10

Cis face receives, trans face ships proteins; 3-20 cisternae containing enzymes

Question 11

Golgi apparatus function

Answer 11

Modifies, sorts, packages, transports proteins received from ER, forms secretory, membrane, and transport vesicles.

Question 12

Lysosome function

Answer 12

Enzymes in membrane digest substances entering cell, cell components (autophagy), whole cell (autolysis)

Question 13

Mitochondria structure + function

Answer 13

Outer and inner membrane, cristae folds embedded with ribosomes. Inner matrix is fluid filled and contains own genome (37 genes) and for mitochondrial specific products.

Question 14

Cytoskeleton function

Answer 14

Fibres/filaments maintain size, shape, integrity (tidy) of cell, interior scaffolding and transport, cell movement.

Question 15

Cytoskeleton fibres/filaments

Answer 15

Microfilaments, intermediate filaments, microtubules

Question 16

Microfilaments structure/location

Answer 16

Two actin strands twisted in long chains, can be assembled/disassembled as required; found in periphery/lining of cell

Question 17

Microfilaments function

Answer 17

Bear tension + weight by anchoring cytoskeleton to PM proteins, can promote amoeboid motility,

Question 18

Intermediate filaments function

Answer 18

Bear tension + weight by cell anchoring, scaffolding for organelles. Most permanent of structures, less dynamic.

Question 19

Intermediate filaments structure/location

Answer 19

Made from different materials including keratin, twisted into a thick multi strand cord, found in cytoplasm.

Question 20

Microtubules structure/location

Answer 20

Made from tubulin dimers (alpha + beta), looks like foam roller. Dynamic, can be assembled or disassembled as required. Extends from centrioles into cytoplasm.

Question 21

Microtubule 4 functions

Answer 21

Guides organelle movement, chromosome separation for cell division, support/movement of cilia and flagella, maintains cell shape and size