BIOL 1030H Lecture Notes - Lecture 2: Mitochondrion, Tubulin, Desmosome

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26 Jun 2018

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Active Transport is movement against a concentration gradient

Examples:

Nutrients: higher on the outside to lower on the inside

•

Waste: higher on the inside and lower on the outside

•

Passive transport works only when the concentration gradient is in the right direction.

Primary Active Transport

Secondary Active Transport

Two kinds of active transport:

Primary active transport uses ATP

Ex: sodium-potassium pump (NA+/K+ATPase) (3 Na: 2 K)

Helps maintain homeostasis

Take protons and pump them outside the cell, using active transport (using ATP)

The proton pump generates an electrochemical gradient with high concentration of protons

outside the cell

Antiporter uses the proton electrochemical gradient to move the other molecule. Brings the

proton back in and exchanges it for a different molecule

Secondary Active Transport- indirectly uses ATP and is a 2 step process

Hypertonic- shrunk

•

Isotonic- Normal

•

Hypotonic- Swollen

•

Very hypotonic- Lysed

•

Cells use active transport to maintain homeostasis

All cells have some kind of plasma membrane

•

Eukaryotic will have organelles inside of them

•

Only difference is that eukaryotic cells have a nucleus

•

Prokaryotic cells have a nucleur region where DNA is located, but no actual nucleus

•

Review 5.3 Animal and Plant cells

•

Prokaryotic vs Eukaryotic

Each organelle has a membrane

•

Transport contents through vesicles

•

Sometimes organelles are physically connected, and some are interconnected through vesicles

•

Eukaryotic cells have an endomembrane system

Double membrane envelope that surrounds the nucleus, keeping everything together

•

Ex: MRNA exits the nucleus via nucleur pores

○

Has nuclear pores- protein complexes, allowing a passage of molecules form inside to outside

and vice versa.

•

Nucleur Envelope

2 components, smooth and rough endoplasmic reticulum

•

Many proteins, including those that are destined for secreation, are synthesized by

ribosomes associated with the smooth endoplasmic reticulum

○

Rough contains rough endoplasmic reticulum

•

Smooth ER

•

Endoplasmic Reticulum

Lecture 2

January 20, 2018

7:00 PM

Biology 1030 Page 1

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Document Summary

Active transport is movement against a concentration gradient. Passive transport works only when the concentration gradient is in the right direction. Nutrients: higher on the outside to lower on the inside. Waste: higher on the inside and lower on the outside. Ex: sodium-potassium pump (na+/k+atpase) (3 na: 2 k) Secondary active transport- indirectly uses atp and is a 2 step process. Take protons and pump them outside the cell, using active transport (using atp) The proton pump generates an electrochemical gradient with high concentration of protons outside the cell. Antiporter uses the proton electrochemical gradient to move the other molecule. Brings the proton back in and exchanges it for a different molecule. All cells have some kind of plasma membrane. Only difference is that eukaryotic cells have a nucleus. Prokaryotic cells have a nucleur region where dna is located, but no actual nucleus. Sometimes organelles are physically connected, and some are interconnected through vesicles.

Related Questions

1 Which of the following statements is false?

(a) CO₂ and O₂ can diffuse freely across the cell membranes.

(b) The differences in permeability between artificial lipid bilayers and cell membranes arise from variations in phospholipid content.

(d) Cells expend energy in the form of ATP hydrolysis to maintain ion concentrations that differ from those found outside the cell.

2 Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell. Which of the following ions is the most abundant inside a typical mammalian cell?

(a) Na⁺

(b) K⁺

(d) Cl^â

3 Pumps are transporters that are able to harness energy provided by other components in the cells and drive the movement of solutes across membranes, against their concentration gradient. This type of transport is called _____________.

(a) active transport.

(b) free diffusion.

(d) passive transport.

harlequinbuffalo618

1. The plasma membrane of liver cells contains a glucose uniportthat transports glucose by facilitated diffusion. When the[glucose] is higher inside the liver cell than the [glucose]outside the liver cell, the glucose uniport will

A. couple the transport of glucose out of the cell to thehydrolysis of ATP

B. couple the transport of glucose into the cell to thehydrolysis of ATP

C. switch to a closed conformation, allowing no transport ofglucose

D. transport glucose out of the cell by passive transport

E. transport glucose in of the cell by passive transport

2. Unlike the positive charged ion shown in the middle diagramof figure 11-4B, K+ is higher in concentration inside the cell. Howwill the membrane potential of a cell at rest (shown in both themiddle and right-hand diagrams of Figure 11-4B) affect theelectrochemical gradient for K+?

A. The membrane potential will increase the electrochemicalgradient

B. The membrane potential will decrease the electrochemicalgradient

C. The membrane potential will have no effect on theelectrochemical gradient

3. Which of the following proteins carries out activetransport?

A. gluclose symport

B. Bacteriorhodopsin

C. ABC transporter

D. NA K pump

E. All of the above

4. Aquaporin will not transport Na+ ions because

A. Two asparagine residues in the channel prevent the passage ofNa+ ions by binding the oxygen of each water molecule as it passesby

B. Na+ ions are repelled by the positive charges at the entranceto the channel

C. Na+ ions cannot make contact with the carbonyl (C=O) groupson all four sides of the channel

D. The passage of Na+ ions is energetically unfavorable becauseone side of the channel is hydrophobic in nature

5. The acetylcholine receptor is different from other channelproteins we have discussed, such as the K+ leak channel,because

A. The acetylcholine channel is composed of a single polypeptiderather than multiple subunits

B. The acetylcholine channel transports Na+ ions against theconcentration gradient for sodium

C. The acetylcholine channel has a much smaller diameter thanother channel proteins

D. The acetylcholine channel transports ions with theirassociated shell of water molecules

E. The acetylcholine channel is always open, and never switchesto a closed conformation

6. After opening briefly along the axon of a neuron,voltage-gated ion channels switch to an inactivated conformationthat slowly returns to the original closed conformation of theprotein. This slow change in conformation, requiring about amillisecond, is important because

A. all of the ions that were transported across the membranewhen the ion channels were open must be actively transported backto the other side of the membrane, restoring the originalconcentration gradient, before the ion channels can open again

B. ATP hydrolysis is necessary to drive this energeticallyunfavorable change in conformation

C. it prevents the action potential from reversing direction andtraveling back toward the cell body of the neuron

D. the channel protein must be dephosphorylated in order tocomplete the transport process and return to the originalnonphosphorylated conformation

limeelephant476

Cells from which domain(s) of life are separated from theirenvironment by a plasma membrane? Select all correct choices.bacteria archaea eukarya 2. The active maintenance of a constantenvironment is referred to as: stability. homeostasis. symmetry.equilibrium. balance. 3. The electrical component of anelectrochemical gradient is due to: the use of ATP as an energysource to drive primary transport. a greater concentration ofpositive charges on the side of the membrane with the highestconcentration of protons. a greater concentration of positivecharges on the side of the membrane with the lowest concentrationof protons. a higher pH on the side of the membrane with the lowestconcentration of protons. a higher pH on the side of the membranewith the highest concentration of protons. 4. Which one of thefollowing would be found in the cells of a blade of grass but notin the cells of an insect feeding on that grass? Select all correctchoices. chloroplasts cytoskeletal elements mitochondriaendoplasmic reticulum nuclei 5. With which of the following is asignal-recognition particle (SRP) capable of interacting? Selectall correct choices. a signal sequence in a protein destined forthe ER a ribosome an SRP receptor 6. Which one of the followingcellular compartments does not have a double membrane structureseparating it from the rest of the cell? Select all correctchoices. mitochondria chloroplasts lysosomes the nucleus 7. True orFalse: purified phospholipids will gather together and formmembranes only if the appropriate enzyme is present. false true 8.Which component(s) of a phospholipid would most likely be found inthe interior of a lipid bilayer? Select all correct choices.glycerol fatty acids phosphate 9. Some drugs are now beingdelivered into cells through liposomes, where the drug issurrounded by a phospholipid bilayer. How do the drugs enter intothe cell? The liposome fuses with the phospholipid bilayer of thecell. The drug destroys the liposome and is transported viadiffusion into the cell. Protein channels on the cell surfacetransport the liposomes into the cell. The liposome cuts a hole inthe cell and injects the drug into the cell. 10. Some diseases canresult from defective transport across the membrane. For example,cystic fibrosis results from a chloride ion transporter that doesnot function. Which of the following would be affected when thistransporter does not function? the electrical gradient of the cellthe chloride concentration gradient Neither the chlorideconcentration gradient nor the electrical gradient of the cell Boththe chloride concentration gradient and the electrical gradient ofthe cell

tealbuffalo995

BIOL 1030H Lecture Notes - Lecture 2: Mitochondrion, Tubulin, Desmosome

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