ASU BIO 181 QUIZ 2 (Module 3 & 4)

What does the nucleosomal core have in it (i.e., the basket ball like structure on the slides)?

(2 H2A, 2 H2B, 2 H3, 2H4)

What are the two functions of a membrane?

- Regulating which molecules go in and out of the cell - Separating incompatible processes occurring within organelles

We are made up of ______ percent water.

50-70%

Molecular motors run on which two cytoskeletal filament systems?

ACTIN FILAMENTS AND MICROTUBULES

Explain the evolutionary origin of mitochondria.

Anaerobic eukaryote engulfed an aerobic alpha-proteobacterium which then became an endosymbiont providing ATP from respiration while receiving substrates and protection

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. The messenger RNA goes directly to the ER. B. A ribosome binds to the mRNA and a short stretch of protein is synthesized that contains a signal sequence. C. Ribosomes at the endoplasmic reticulum bind to the protein D. Is a random event and one day the protein could go to the ER and on another day the same protein could associate with a free polyribosome. E. None of the above.

B. 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?

Because the inside of the phospholipid bilayer of the cell membrane is hydrophobic, this one hydrophobic peak indicates the glycophorin only cross the phospholipid bilayer once, and thus a single pass protein. Multi pass proteins cross the plasma membrane multiple times.

When a vesicle fuses with the plasma membrane the contents of the lumen of the vesicle are: A. Ligands that enter the nucleus. B. Ligands that become the part of the plasma membrane. C. Ligands that are used in cell communication. D. Two of the above. E. Part of the nuclear pore complex.

C. Ligands that are used in cell communication.

Consider the geography of cells. Actin filaments are present in the cell's ___ and the microtubules are present in the cell's

CELL CORTEX; CELL INTERIOR

The plasma membrane gets new lipids from: A.The lumen of the ER. B. The lumen of the Golgi apparatus. C. Making new lipids at the plasma membrane. D. The nucleus. E. None of the above.

E. None of the above

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

FALSE

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

FALSE

Chromosomes are made out of Euchromatin.

FALSE

Cilia and microvilli contain a similar number of parallel actin filaments.

FALSE

Heterochromatin does not exist in interphase nuclei.

FALSE

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

FALSE

The ER is contiguous with the Golgi apparatus.

FALSE

The actin filament system extends outside of the cell.

FALSE

The actin filament system is present in the nucleus.

FALSE

The diameter of an intermediate filament is 25 nm.

FALSE

Cholesterol is _____ to have in biological membranes.

Good

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

Hydrophilic

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

Hydrophilic and Hydrophobic.

Which cytoskeletal filament system lines the inside of the nucleus to protect it?

Intermediate filament system. Lamins are type V intermediate filament proteins.

What are the orphaned organelles orphaned from?

Orphaned from the endomembrane system

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

TRUE

Molecular motors use ATP as the energy source to power the molecular motors.

TRUE

Naked DNA does not exist in Nature but scientists can make naked DNA in a test tube.

TRUE

The ER is contiguous with the nuclear envelope.

TRUE

To get into the nucleus a component has to have the correct signal sequence and pass through a nuclear pore.

TRUE

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

The endoplasmic reticulum (ER) plays a key role in the modification of proteins and the synthesis of lipids. The Endoplasmic reticulum, Golgi, and vesicles all evolved from the endomembrane system which is when the cells surface became flexible many millions of years ago due to losing the cell wall. This allowed for the exchanging of material with the environment to happen rapidly, which then lead to the cell to sustain a larger volume and have a more rapid metabolism.

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

The vesicles are carried from the Golgi to the plasma membrane by the microtuble system (which doesn't reach all the way to the plasma membrane) so then it later goes to the actin filament system (which are connected to plasma membrane)

What is the difference between a triglyceride and a phospholipid?

Triglycerides have three fatty acids attached to the glycerol whereas phospholipids have one of the fatty acids replaced by a phosphate group.

Where is the histone H1 found?

Used as a staple to attach DNA to nucleosomes