Lect 1: Intro Cell

Compare similarities and differences between cytoplasm and cytosol

- Cytoplasm contains organelles - Cytosol does not contain any organelle

Compare similarities and differences between nuclei and mitochondria

-Similarities: • Surrounded by a double membrane • Contain DNA - Differences: • Nucleus contains chromosomal DNA, produce RNA and ribosomes, there is one nucleus • Mitochondrion does not contain chromosomal DNA but only has mitochondrial DNA, there are many mitochondria and they produce ATP

Is the following statement correct? "Glycolipids move between different membrane enclosed compartments during their synthesis but remain restricted to one side of the lipid bilayer."

Correct. Glycolipids are mostly restricted to the monolayer of membranes that faces away from the cytosol. Some special lipids, such as phosphatidylinositol are found specifically in the cytosolic monolayer

How can you extract membrane proteins and lipids from cells?

Detergents can solubilize membrane proteins and lipids.

Plants are composed of procaryotic cells.

False. Plants are composed of eucaryotic cells that contain chloroplasts as cytoplasmic organelles. The chloroplasts are thought to be evolutionary derived from procaryotic cells.

Protozoans are complex organisms with a set of specialized cells that form tissues, such as flagella, mouthparts, stinging darts, and leg-like appendages.

False. Protozoans are single-cell organisms and therefore do not have different tissues. They have a complex structure, however, that has highly specialized parts.

The cytosol contains membrane-enclosed organelles, such as lysosomes.

False. The cytosol is the cytoplasm excluding all organelles.

The hereditary information of a cell is passed on by its proteins.

False. The hereditary information is encoded in the cell's DNA, which in turn encodes its proteins.

Compare the properties between human cells and bacterial cells

Human cells Bacterial cells Classification: Eucaryotic Procaryotic Size: 20-30 µm 1-3 µm Localization of DNA: Nucleus Cytosol Possess organelles; Yes No Possess cell well; No Yes Possess plasma membrane; Yes Yes Possess cytosol; Yes Yes Possess ribosome; Yes Yes

Can lipids in a lipid bilayer flip-flop freely from one lipid monolayer to the other?

No, they cannot do so freely unless with the help of enzymes.

Compare similarities and differences between ER and Golgi apparatus

Similarities: • Surrounded by a single membrane • There is one ER and one Golgi apparatus - Differences: • ER is involved in synthesize and transport lipids and membrane proteins • Golgi apparatus is involved in modifying, sorting, and packing lipids and membrane proteins for secretion or for delivering to other organelle

Bacterial DNA is found in the cytosol.

True. Bacterium does not have a nucleus

Lysosomes and peroxisomes are the site of degradation of materials.

True. Peroxisomes and lysosomes contain enzymes that catalyze the breakdown of substances produced in the cytosol or taken up by the cell.

Nuclei and mitochondria are surrounded by a double membrane

True. The nuclear envelope is a double membrane, and mitochondria are surrounded by both an inner and an outer membrane.

Can lipids rotate and move within the monolayer of a lipid bilayer?

Yes, they can do so freely.