Bio Exam Review 2

Exocytosis

vesicles form naturally during this process

The Endomembrane System

where are the lysosomes located

The endomembrane system

where is the ER located

The Endomembrane System

where is the Golgi apparatus located

The Endomembrane System

where is the nuclear envelope located

b) Scanning Electron Microscopy

A biologist is studying kidney tubules in small mammals. She wants specifically to examine the juxtaposition of different types of cells in these structures. The cells in question can be distinguished by external shape, size, and 3-dimensional characteristics. Which would be the optimum method for her study? a) Light Microscopy b) Scanning Electron Microscopy c) Electron Microscopy

ER signal sequence

A glycosyltransferase protein that resides in the RER would have which of signal sequences?

b) will decrease

A negative membrane potential ------ the diffusion of negatively charged ions into the cell. a) will increase b) will decrease c) will have no effect on d) may or may not have an effect

a) will increase

A negative membrane potential ------ the diffusion of positively charged ions into the cell. a) will increase b) will decrease c) will have no effect on d) may or may not have an effect

c) will have no effect on

A negative membrane potential ------ the diffusion of uncharged molecules into the cell. a) will increase b) will decrease c) will have no effect on d) may or may not have an effect

b) Active Transport

A substance can be transported against its electrochemical gradient by ________ a) Passive Transport b) Active Transport c) Secondary Active Transport d) Primary Active Transport

No, this statement is false. Microfilaments are made of actin and Microtubules are made of Tubulin.

Are both microfilaments and microtubules made up of the same protein monomers?

Yes, both are false

Are the following statement about nuclear pores true or NOT? a) Movement of large molecules such as protein complexes is completely blocked by the nuclear pore complex. b) A nuclear pore is a big hole created in the phospholipid bilayers due to strong hydrophobic interactions in the double membranes.

FALSE

Are these statements about NLS true or false? - NLS is a signal peptide that directs protein - Binding of NLS to importin allow complex (nuclear protein + importin) to move across a nuclear envelope via simple diffusion

increase, increase

As an object___ in size, the volume___ more rapidly than the surface area

Ouabain binds inside the membrane to prevent the pump from moving properly

Based on our understanding of cell membranes, how do you think Ouabain inhibits the sodium-potassium pump? a) Ouabain binds inside the membrane to prevent the pump from moving properly b) It helps it move more properly

high

Cells a prefer ____ surface area to volume

Yes, all are correct

Consider the plasma membrane of an animal cell that contains a sodium-potassium pump as well as two non-gated (always open) ion channels: a Na+ channel and a K+ channel. The effect of the sodium-potassium pump on the concentrations of Na+ and K+, as well as the distribution of charge across the plasma membrane is indicated in the figure below. Do the following statements correctly describe(s) the driving forces for the diffusion of Na+ and K+ ions through their respective channels? a) The diffusion of Na+ ions into the cell is facilitated by the Na+ concentration gradient across the plasma membrane. b) The diffusion of K+ ions out of the cell is impeded by the electrical gradient across the plasma membrane. c) The electrochemical gradient is larger for Na+ than for K+.

a) D b) E

Considering sodium and potassium bind to this protein, what amino acids do you expect to be in the binding site? a) D b) E c) K d) A e) L

a) Microfilaments c) Microtubules

Directional movement is required for a number of processes within the cell. For example, the targeted movement of vesicles in the cytoplasm occurs in a specific directional manner. To ensure that movement occurs in only one direction, the fibers that control the movement must have polarity, so that one end of the fiber differs from the other. Which of the three cytoskeletal fibers have polarity? a) Microfilaments b) Intermediate Filaments c) Microtubules

a) the Insulin would be unable to attain its tertiary structure

If the ER vesicle was mistargeted and fused with the cell membrane instead of the Golgi, what would the result be? a) the Insulin would be unable to attain its tertiary structure b) it will stay in the ER c) It will become a tertiary structure

a) the surface area increases c) the volume increases more rapidly than the surface area e) the surface area-to-ratio decreases

If you approximate a cell as a sphere, as shown in the image, as the volume of the cell increases: a) the surface area increases b) the surface area decreases c) the volume increases more rapidly than the surface area d) the volume decreases more rapidly than the surface area e) the surface area-to-ratio decreases f) the surface area-to-ratio increases

b) (1) The new solute will diffuse from left to right to establish equilibrium. (2) The water level on the right will fall.

Imagine a beaker with solutions separated by a planar membrane (as shown in the image). Predict what will happen after addition of a new solute to the solution on the left side, if the new solute (1) crosses the membrane readily or (2) is incapable of crossing the membrane. a) (1) the new solute will diffuse right to left to establish equilibrium. (2) The water level on the left will overflow b) (1) The new solute will diffuse from left to right to establish equilibrium. (2) The water level on the right will fall. c) There will be no effect and they are already equilibrium

The proportions of proteins, lipids, and carbohydrates will vary

In addition to a plasma membrane, eukaryotic cell organelles such as mitochondria also have membranes. In which way would these membranes differ?

- RER - Golgi

In eukaryotic cells, sugar residues are covalently attached to proteins through the process of glycosylation. This posttranslational modification occurs: (select all that apply) - mitochondria - RER - SER - Golgi apparatus - Nucleus

a) on the inside surface of the vesicle

In receptor-mediated endocytosis, receptors initially project to the outside of the cell. For example, insulin receptors are found on the surfaces of cells. Insulin binds to the insulin receptor on the plasma membrane. Upon insulin binding, the active insulin receptor is then internalized. Where do insulin-bound insulin receptors end up after endocytosis? a) on the inside surface of the vesicle b) on the outside surface of the vesicle c) in the ER

1) Rough ER 2) Cis-Golgi 3) Trans-Golgi 4) Transport Vesicles containing mature proteins 5) Cell Membrane

Insulin is a protein secreted by the cells of the pancreas. Put the following in the correct order to show the pathway for the synthesis and secretion of insulin. a) Cell Membrane b) Cis-Golgi c) Rough ER d) Trans-Golgi e) Transport vesicles containing mature proteins

No, glucose is not charged which means it needs Na+ to move it across the membrane.

Is glucose charged? Yes, or NO? And what does this mean about its electrochemical gradient?

The nuclear membrane is part of the endomembrane system as it is continuous with the rough endoplasmic reticulum.

Is the nuclear membrane part of the endomembrane system? If so, which other organelle is it continuous with?

False

Is this statement about lysosomes true or false? Lysosomes contain an array of enzymes capable of breaking down various biological polymers—proteins, carbohydrates, and lipids but not nucleic acids

proteins, nucleic acids, and polysaccharides

Larger molecules consist of ___ , ___, and ____ and they cannot fit through membrane transport proteins

double bonds

Lipid composition is the number of ___

Myosin: associates with microfilaments for cellular contraction Kinesin: associates with microtubules to deliver cargo to the positive end Dynein (cytoplasmic): associates with the microtubules to deliver cargo to the negative end Dynein (linked): associated with the microtubules to flex cilia for cellular movement

Match Each term with the correct definition: Terms: Myosin Kinesin Dynein (cytoplasmic) Dynein (linked) Definition: - associates with microfilaments for cellular contraction - associates with microtubules to deliver cargo to the positive end - associates with the microtubules to deliver cargo to the negative end - associated with the microtubules to flex cilia for cellular movement

Dyneins: they undergo reversible shape changes via ATP hydrolysis. Microtubules: nine fused pairs form an outer cylinder and one pair of unfused one runs up the center. Nexins: they cross-link the pairs of microtubule doublets and limit how far the doublets can slide.

Match the proteins with its functional of physical properties n cilia: Terms: Dynein's Microtubules Nexins Definition: - they undergo reversible shape changes via ATP hydrolysis. - nine fused pairs form an outer cylinder and one pair of unfused one runs up the center. - they cross-link the pairs of microtubule doublets and limit how far the doublets can slide.

Rolling: Integrin and recycling endosomes Crawling: Microfilament assembly/disassembly

Match the term with the definition: Terms: Rolling Crawling Definitions: Integrin and recycling endosomes Microfilament assembly/disassembly

positively charged

NLS contain___ amino acids

fatty acid chains

Nonpolar parts insert the _____ in the interior of the cell membrane

interior of the cell membrane

Nonpolar parts insert the fatty acid chains in the _____

proteins, carbohydrates, and lipids

Phospholipid bilayer is made up of ___ , ____, and _____

selective permeability

Phospholipid bilayers have ___

bilayers

Phospholipids form ___ in aqueous solutions

a) Mitochondria c) Nucleus d) Endoplasmic reticulum e) Golgi apparatus

Plant cells and animal cells share many of the same structures, but each type of cell also has unique structures. Which of these structures are found in BOTH plant and animal cells? a) Mitochondria b) Nucleoid c) Nucleus d) Endoplasmic reticulum e) Golgi apparatus f) vacuole

pseudopodia

Polymerized actin is called

Co-translation translocation

Protein packaged for delivery to lysosomes, cell membrane, or secreted from the cell

K, S, N, Y (positively charged and polar amino acids)

Proteins associate with membranes through non-covalent interactions. Which amino acids would you expect to find on the surface of proteins in the protein coat model? a) K b) L c) S d) M e) N f) D g) Y

The order is: - Phagocytosis - Phagosomes fuse with a primary lysosome - The food particle is digested in the secondary lysosome - the recyclable material diffuses into the cytoplasm - Exocytosis of undigested materials

Sort the steps of lysosomal digestion from the point where the food particle is taken into the cell: - Phagocytosis - Exocytosis of undigested materials - The food particle is digested in the secondary lysosome - Phagosomes fuse with a primary lysosome - the recyclable material diffuses into the cytoplasm

TRUE

The microvilli have a similar structure to the cilia but cannot move independently to propel the cell forward. Is the main reason for this below true or false? a) The microfilaments do not have motor proteins present like the microtubules.

Cholesterol

The OH group of ___ interacts with the polar heads of phospholipids

polar heads

The OH group of cholesterol interacts with the ____ of phospholipids

Light Microscopy allows one to view dynamic processes in living cells

The advantage of light microscopy over electron microscopy is that ___________.

a) the function of the Golgi apparatus in sorting and directing membrane components

The difference in lipid and protein composition between the membranes of the endomembrane system is largely determined by the ____. a) the function of the Golgi apparatus in sorting and directing membrane components b) the function of the ER in sorting and directing membrane components

a) This process involves receptor proteins located on the cell's surface b) Coated pits are lined on their cytoplasmic surface by clathrin d) Coated vesicles contain materials that were previously extracellular e) the vesicle loses its clathrin coat inside the cell

The figure shows the process by which botulinum toxin enters neutrons. Which of the following statements about this process is TRUE? a) This process involves receptor proteins located on the cell's surface b) Coated pits are lined on their cytoplasmic surface by clathrin c) Coated vesicles eventually become part of the endoplasmic reticulum d) Coated vesicles contain materials that were previously extracellular e) the vesicle loses its clathrin coat inside the cell

cytoskeleton

The overall shape of an animal cell is determined by its ________

a) replacing saturated fatty acids with unsaturated fatty acids.

The plasma membrane of the bacterium Pseudomonas syringe is able to remain fluid when it is extremely cold. The bacterium most likely accomplishes this by a) replacing saturated fatty acids with unsaturated fatty acids. b) replacing unsaturated fatty acids with saturated fatty acids

They are NOT true.

There are proteins and polysaccharides in both the plant cell wall and animal extracellular matrix. Are the following statements is true or NOT about where these molecules are made and how they get into the extracellular structures? a) nascent proteins are made on ribosomes and then enter the ER by binding to importin. b) folded proteins are secreted to the extracellular region by endocytosis.

nuclear pores

Traffic across the nuclear envelope occurs through

Cytosol

Translocation of mRNA into protein by a ribosome by

V, I, A, F (non-polar amino acids)

Transmembrane proteins often have one or more alpha helices within the membrane, as shown in the image. Recall that amino acid side chains extend out from the alpha helix. What amino acids would you expect to find in the helix? a) V b) K c) A d) F e) I

False, they are not.

True or False: Are both microfilaments and microtubules made of several fibrous proteins?

The proteins do not go through the Golgi apparatus and remain free in the cytosol

What happens to the proteins that are synthesized on free ribosomes and fully folded in the cytoplasm? Do they go through the Golgi apparatus or remain in the cytosol?

a) Lipid

What kind of molecule does Ouabain look like? a) Lipid b) Nucleic Acid c) Carbohydrates

Fatty Acid

What molecule are the hydrophobic tails called?

Nuceloid

What organelle is the location of genetic material in prokaryotic cells?

alpha helices

What secondary structure is the most common in the sodium-potassium pump? - alpha helices - beta-sheets

The Endomembrane system

Where are the vesicles located

The Endomembrane System

Where is the cell membrane located

a) Cell Membrane c) Nucleus

Which cellular structures interact directly with the intermediate filaments? Select all that apply. a) Cell Membrane b) Extracellular Matrix c) Nucleus d) Mitochondria

a) Both mitochondria and chloroplasts have their own DNA that encodes some of the proteins used by the organelles to carry out their biological functions

Which characteristic of mitochondria and/or chloroplasts present in modern cells is one of these pieces of evidence? a) Both mitochondria and chloroplasts have their own DNA that encodes some of the proteins used by the organelles to carry out their biological functions b) They cannot survive on their own

c) lysosomes d) RER e) Golgi appartus g) SER

Which of the following are components of the endomembrane system? Select all that apply a) Mitochondria b) Nucleoid c) lysosomes d) Rough Endoplasmic reticulum e) Golgi apparatus f) vacuole g) Smooth Endoplasmic Reticulum

a) In human cell membranes, it makes membranes more rigid (viscous) at higher temperatures but more fluid at lower temperatures.

Which of the following is true of cholesterol? a) In human cell membranes, it makes membranes more rigid (viscous) at higher temperatures but more fluid at lower temperatures. b) In human cell membranes, it makes membranes more rigid (viscous) at lower temperatures but more fluid at higher temperatures.

b) channels c) carrier proteins

Which of the following membrane proteins are involved in passive transport? Select all that apply. a) pumps b) channels c) carrier proteins

b) The outside of the cell is more positive than the inside because more positive ions are pumped out of the cell than are pumped in.

Which of the following statements correctly describes the effect the sodium-potassium pump has on the distribution of charge across the plasma membrane? a) The inside of the cell is more positive than the outside because more positive ions are pumped in the cell than are pumped out b) The outside of the cell is more positive than the inside because more positive ions are pumped out of the cell than are pumped in. c) There is no effect

a) Ribosomes

Which of the following would you expect to find in both a eukaryotic cell and a prokaryotic cell? a) Ribosomes b) Chloroplast c) Vacuole d) Peroxisomes

Translation

Which process occurs on ribosomes? Translation or Transcription

a) Collagen b) Keratin d) Laminin

Which protein is not part of the structure of a cilium? Select all that apply. a) Collagen b) Keratin c) Nexin d) Laminin e) Dynein f) Radial Spokes

b) Adhesion

Which word identifies the functional role of the extracellular matrix in the figure? a) transmembrane b) Adhesion c) internal

(1) Kinesin (2) Microtubules

_____ (1) is a motor protein that carries vesicles by "walking" along _____ (2) toward the plus end

signal sequences (location sequences)

___on the protein direct them to specific organelles of extracellular locations

Proteins

are embedded inside phospholipid bilayers

Phospholipids

are major components of membranes

amphipathic

both hydrophilic heads and hydrophobic tails

carrier proteins

change their shape during transport process

passive diffusion

channel proteins facilatate the _____

Peroxisome

collects toxic peroxides and breaks them down

Prokaryotes

contain small, circular DNA molecules

ER to golgi to cell membrane

describe the process of which a protein travels through co-translocation

Channel proteins

facilitate the passive diffusion

electrochemical gradient

facilitated diffusion is driven by both a concentration and _____

transmembrane protein

has to travel out of the phospholipid bilayer from the bottom all the way through

amphipathic

integral proteins are___

cholestorol

is a key component of animal cells

Smooth ER

lipid synthesis

NLS (nuclear localization signal)

marks amino acid sequence for transport

Lumen

protein is folded and modified

Post Translational Location

proteins sent to organelles within the cell

Nucleus

site of DNA replication and transcription

Rough ER

synthesizes proteins

Glycosylation

tags proteins for delivery to different parts of the cell or export

a) lysosomal digestion

the activity of the hydrolytic enzymes within the secondary lysosome is the: a) lysosomal digestion b) description of Golgi apparatus c) Vesicles digestion