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Are lysosomes visible with a light microscopic ?

Yes, ( unlike the plasma membrane, which needs EM)

Are proteasomes membranous or non-membranous ?

Non-membranous ( cylindrical structure )

At what PH do lysosomal enzymes work optimally, and why doesn’t leakage harm the cell ?

optimal at acidic PH ( ~ 5.0) , if leaked, the enzymes are practically inactive at the neutral cytosolic PH (~7.2), so they’re harmless.

At which Golgi face would you expect a newly arrived transport vesicle from the RER to fuse - cis or tans ?

Cis face

Give 2 examples of cytoplasmic inclusions

Lipid droplets and glycogen granules ( also pigment granules like “melanin ,lipofuscin,hemosiderin”

Give an example of a non-membranous organelles ?

Ribosomes

Give three examples of membranous organelles

Golgi apparatus, rER,sER..( also mitochondria , lysosomes,peroxisomes)

Give two medical fields where cell biology is directly applied

Pharmacology - disease diagnosis and treatment

How are glycogen granules visualized histologically

As irregular clumps that are PAS ( periodic acid-schiff)-positive or electron-dense,notably in liver cells.

How are peroxisomes enclosed ?

By a single membrane ( spherical organelles)

How do inclusions differ from organelles ?

inclusions have little or no metabolic activity themselves; they’re metabolic products, not active machinery.

How much greater is the ER’s membrane surface area compared to the plasma membrane ?

Up to 30 times greater

If you see a faint line between two adjacent cells under a LIGHT microscopic , what is actually made of ?

Plasma membrane proteins and extracellular matrix ( not the lipid bilayer itself , which is hard to be seen in the light microscope).

In which organs\cells are peroxisomes especially large and abundant ?

liver and kidney cells ( important for detoxifying drugs\toxic molecules)

Is smooth ER basophilic ?

no - it lacks polyribosomes , so it is NOT basophilic , and is best seen with TEM .

Is the rough ER continuous with the nuclear envelope ?

Yes - its membrane are continuous with the outer membrane of the nuclear envelope.

List the 3 main functions of the plasma membrane …

(1) selective barrier regulating transport , (2) maintains constant ion content of cytoplasm vs   Extracellular fluid , (3) recognition\signaling via membrane proteins.

Name the two components of the cytoplasmic matrix ?

Inorganic components ( ions: Na+ , k+ , Ca2+)and organic components (carbohydrates , lipids , proteins , RNAs)

Name the two mitochondrial membranes and one feature of each 

Outer membrane - contains voltage -dependent anion channels.

Inner membrane - folded into Cristal, increasing surface area.

Predict :  what would happen to membrane fluidity / stability if a drug depleted membrane cholesterol ? 

the membrane would become more fluid and less stable \ mechanically weaker ( cholesterol normally moderates fluidity and adds ridgity\ stability)

Roughly how many cells does the average adult human body contain ?

40 trillion cells

True or false : cells are the basic structural and functional unit of unicellular organism only 

False- they are the basic unit of ALL multicellular organisms too

True or false : cells are the basic structural and functional unit of unicellular organism only 

False- they are the basic unit of ALL multicellular organisms too

Under what microscope can the plasma membrane actually be seen ?

The electron microscope only ( not the light micro )

What allows each organ (and the organism as a whole) to function properly ?

the precise, orderly arrangement of tissues within organs.

What are the integral ( transmembrane) proteins VS peripheral proteins ?

Integral proteins are embedded within the bilayer ; peripheral proteins attach to the membrane surface only.

What are the intercommunicating within the ER called ?

Cisternae

What are the two functional faces of the Golgi , and a what happens at each ?

Cis face ( receiving side, where transport vesicles merge in ) and trans face ( shipping side , where processed proteins exit) 

What are the two major compartments of a cell ?

The cytoplasm and nucleus

What are the two major structural components of a proteasomes ?

The core (CP) and the regulatory particle (RP)

What are the two subunit of a ribosome, and what do they contain ?

a small and a large subunit , each containing rRNA ( of different lengths ) and various proteins.

What breaks down the H2O produced , and why is this necessary ?

Peroxidases such as catalase-because H2O is potentially damaging to the cell

What carries material from the RER to the Golgi apparatus ?

Transport vesicles

What determines how many mitochondria a cell has ?

The cell’s energy needs

What distinguishes membranous from non-membranous organelles ?

membranous organelles have their own plasma membrane seperating their internal environment from the cytoplasm ; non-membranous ones do not .

What distinguishes membranous from non-membranous organelles ?

membranous organelles have their own plasma membrane seperating their internal environment from the cytoplasm ; non-membranous ones do not .

What do oxidases in peroxisomes produce?

H2O2 ( hydrogen peroxide) , by removing hydrogen atoms from substances and transferring them to O2

What does “amphipathic “ mean , in the context of the phospholipid?

Hydrophobic (non polar) and Hydrophilic (polar) 

What is cell biology also known as ?

Cytology

What is found within the mitochondrial matrix ?

several enzymes, plus a small circular DNA chromosomes, ribosomes,mRNA,and tRNA ( similar to bacterial components).

What is hemosiderin?

an iron-storage complex found within the cytoplasm of many cells.

What is polyribosomes ( polysome)?

A complex of many ribosomes bound to the same strand of mRNA during protein synthesis

What is smooth ER’s main functional speciality ?

Lipid metabolism

What is the aqueous gel of the cytoplasm called ?

The cytoplasmic matrix

What is the average thickness of the plasma membrane ?

7.5-10 nm

What is the correct hierarchy of body organization presented ?

Cell —→ tissue —→ organ —→ body system .

What is the cytoplasm, structurally ?

The part of the cell located in the nucleus

What is the function of proteasomes ?

degrade target proteins into small peptides, removing proteins no longer needed and controlling protein activity duration.

What is the Glycocalyx (cell coat) ?

The layer formed by carbohydrates chains attached to membrane proteins ( glycoproteins) and lipids ( glycolipids) on the extracellular surface . 

What is the main biochemical function of the Golgi apparatus ?

completes post translational modification of proteins made in the RER, then packages / addresses them to their proper destinations.

What is the main functional of the lysosomes ?

Intracellular digestion and turnover of cellular components - the cells “ digestive organelles”

What is the main functional of mitochondria ?

Aerobic respiration and production of ATP ( high -energy phosphate bonds) to supply energy for cellular activates.

What is the main functional speciality of ribosomes ?

Site of protein synthesis- assembling polypeptides from amino acids in a sequence specified by mRNA .

What is the size range of lysosomes ?

0.05-0.5 um in diameter

What is the size range of ribosomes ?

15-30 nm

What model describes the dynamic organization of the plasma membrane ?

The fluid mosaic model

What molecule inserts between phospholipids to modulate membrane fluidity ?

Cholesterol

What pigment protects skin cells from UV radiation ?

Melanin

What shape do smooth ER cisternae typically have, compared to rough ER ?

SER cisternae are more tubular\sacklile , rather than stacked flattened cisternae like RER .

What structural feature distinguishes rough ER from smooth ER ?

Rough ER has polyribosomes attached to its cytotoxic surface; smooth ER lacks them

What is the key difference between lysosomes and proteasomes in what they digest

Lysosomes digest organelles\membranes via autophagy ; proteasomes degrade individual free protein molecules

Where is the intermembrane space located, and what is it similar to chemically ?

between the inner and outer mitochondrial membranes ; similar to cytoplasm with respect to ions\small molecules.

Which cell types are especially rich in rough ER , and why ?

Cells specialized for protein secretion e.g., pancreatic acinar cells (digestive enzymes ) and fibroblasts (collagen).

Which part of the phospholipid is hydrophilic ?

The head ( bears the phosphate group) , the two fatty acids are hydrophobic 

which pigment accumulates especially in stable, non-dividing cells like neurons and cardiac muscle, and is derived partly from lysosomal digestion residues?

Lipofuscin

Why does mitochondrial DNA resemble bacterial DNA ? 

It reflects the endosymbiotic origin of mitochondria ( small circular chromosomes ,similar to bacteria ) - this is implied by the slide’s comparisons.

Why does rough ER stain basophilic under the light microscope?

because of the RNA in the polyribosomes attached to its surface 

Why isn’t the membrane a completely rigid structure or a completely fluid liquid ?

because membrane fluidity is a compromise - it allows lateral protein movement while still maintaining organized structure needed for specialized functions.