Bio 181 Self Check 3

It is a simple matter (i.e., thermodynamically favorable) for a vesicle to form from the endoplasmic reticulum. T/F

False

The ER is contiguous with the Golgi apparatus. T/F

False

The ER is contiguous with the nuclear envelope. T/F

False

Active transport uses ATP to move components in parallel with their concentration gradient, that is: from a high concentration to a low concentration. T/F

False

We are made up of ______ percent water

50-70

For a protein to enter the endoplasmic reticulum as part of the endoplasmic reticulum's lumen or part of the endoplasmic reticulum's membrane....

A ribosome binds to the mRNA and a short stretch of protein is synthesized that contains a signal sequence.

What is the difference between a single-pass transmembrane protein and a 7-pass transmembrane protein?

A single pass transmembrane only passes through the membrane one time. It also incapable of being a channel because the hole present is too small for molecules ot go through. If molecules tried to go through the channel, it would break up the hydrogen bond which would cause the protein to spring out of the cell, essentially killing it. A 7 pass transmembrane protein passed thorugh the membrane 7 different times. It is a channel for different molecules to go through. The make up of the proteins determine what it is specifically a channel for.

A single pass trans-membrane protein that is an alpha helix can make a channel. T/F

False

Cholesterol is _____ to have in biological membranes.

Good

Amino acids can be largely subdivided into two groups. What are the two groups?

Hydrophobic and hydrophilic

When a vesicle fuses with the plasma membrane the contents of the lumen of the vesicle are:

Ligands that are used in cell communication.

Draw a phospholipid and make sure the numbers of carbons are clearly identified

Look at slide 14 on lecture 3a

What are the two functions of a membrane?

Partition water and compartmentalize enzymes to increase the efficiency of chemical reactions

Explain the evolutionary origin of mitochondria

Primitive proto eukaryotic (PPE) cell runs into a primitive proto prokaryotic (PPP) cell. This PPP cell is good at making ATP. It is assumed that the PPE was sick and could not digest food very well, which probably means it had low energy and was low on ATP. The PPE ate the smaller cell (PPP), and it is still living because it is not bothered by the things trying to digest it because of the cell's sickness. So, the PPP starts doing what it usually does, which is making ATP. The ATP makes it into the cytoplasm of the infected cell that ate it. This process made the bigger cell healthy which lead to the evolution of the endosymbiotic relationship between the two

Explain how the vesicles are carried from the Golgi apparatus to the plasma membrane.

Proteins pull on the membrane, and the membrane eventually forms a small neck shape. That small neck shape is then closed off, and that is the start of a vesicle which is filled with lipids and proteins from the lumen of both the endoplasmic reticulum (either rough or smooth) and the Golgi apparatus. This vesicle travels down from the Golgi apparatus to the plasma membrane through the molecular motor system. The vesicle is passed off to the filaments which help this vesicle fuse into the plasma membrane. When the plasma membrane fuses with the vesicle, new lipids are brought to the membrane, but this is also how the membrane gets new Transmembrane proteins (TMP), which will become receptors for the cell to detect ligands. If it is not TMP (there are always lipids in the vesicle), the membrane will expel out of the cell a different type of protein (a ligand) which is what is used to communicate with other surrounding cells.

If something is soluble in water a ____ of hydration forms around it and it is termed _____

Shell; hydrophilic

Explain the evolutionary origin of the endoplasmic reticulum, Golgi apparatus and vesicles

The endomembrane system that resulted as the primitive proto prokaryotic cell evolving into the primitive proto-eukaryotic cell gave rise to many membranes in addition to the plasma membrane. The endomembrane system gave rise to a new type of protein synthesis AND a site where new lipids are made. Those sites are the endoplasmic reticulum (ER) and the Golgi apparatus (GA). Vesicles are used to transport those lipids and proteins from the ER to the GA to the plasma membrane

The plasma membrane gets new lipids from:

The lipid of the membrane from the vesicle after leaving the GA

What are the orphaned organelles orphaned from?

The orphaned organelles are the mitochondria and cytoplast. These two organelles are believed to have evolved from endosymbosis system, which is what makes them orphaned from the endomembrane system.

Facilitated diffusion uses a channel protein to let components move down their concentration gradient. T/F

True

What is the difference between a triglyceride and a phospholipid?

Where one of the carbons covalently links to. In a triglyceride, the carbon links to the end of the glycerol. In a phospholipid, the carbon links to the head group.