BIOLOGY 2A03 Lecture 2: Bio 2a03-week2

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ochreweasel59

25 Dec 2015

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Transport across membranes important for physiological function. Membranes provide a selective barrier to control movement in and out of cells. Ex. | o2 from lungs to body: mediated transport. Different types of cells use different methods of mediated transport molecules such as glucose. Primary active transport: needs atp to work. Secondary active transport: uses electrochemical gradient of ions to get into the cell. Diffusion: the movement of molecules from one location to another due to random thermal motion. This movement happens in both directions i. e. some. Flux: movement from one compartment to another per unit time particles also move back to the original corner (rate of diffusion) Net flux: flux 1 flux 2 and is in the direction of lower concentration: flux occurs in both directions, but the net flux is in the direction of lower concentration. Net flux is from the compartment with the higher concentration to that with the lower concentration.

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

Cellular biology answer check. please check if my answers arecorrect or not.

1) The concentration of ions inside a cell is the same as theirconcentration outside of the cell. True or false? (i chose falsesince having equilibrium inside a cell is bad)

2) Membrane transport proteins...

a)...transport membrane potentials between cells

b)	...transport membranes from the ER to the Golgi

c)	...are made up of phospholipids

d)	...transport molecules across membranes

i chose d

3)The electrochemical gradienttakes into account:

a)	The concentration of solutes on either side of themembrane.

b)	The overall charge on either side of the membrane.

c)	Both of these.

i chose C. (although i am sure that overall charge matters, Iwasn't sure if concentration of solutes are taken account.)

4) If no energywere expended by an animal cell:

a)	Both gradients would be depleted

b)The K+ gradient would maintain itself.

c)	None of these

d)	The Na+ gradient would maintain itself.

I chose d) mainly because I think Na+ gradient exist in animalcell and not K+ gradient.

5) Which of the following is a true statement aboutactin?

a)	Once actin has polymerized, it never depolymerizes.

b)	Actin is a transmembrane protein.

c)	Actin can form branched networks.

d)	Actin filaments are organized into hollow tubes.

I chose c. can't explain why.

6)Ion channels:

a)	Form a hydrophobic channel through the membrane

b)	Have filters that let sugars through

c)	Are selective for particular ions (only the

taupeshark376

Question 401 pts

Kinetic energy is the stored energy that can be used for motion.

True

False

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Question 411 pts

When an electron is transferred from one atom to another, and the two atoms are then electrically attracted to one another, a(n) ________________ bond is formed.

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Question 421 pts

Changing the number of ____________ of an atom would change the chemical properties of the atom.

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Question 431 pts

Forming molecules and breaking down molecules in biological organisms usually requires the use of _________ to help the reaction proceed faster.

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Question 441 pts

Organic molecules have a core composed of .

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Question 451 pts

The building blocks of carbohydrates are

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Question 461 pts

Water molecules crossing a membrane from high to low concentration is .

active transport

cell fate

facilitated diffusion

osmosis

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Question 471 pts

Choose the membrane molecule responsible for the passage of polar molecules and ions into and out of the cell.

phospholipids

transmembrane channel proteins

cell surface proteins

carbohydrate chains

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Question 481 pts

The simplest cells are .

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Question 491 pts

Which of the following membrane bound organelles are found inside bacterial cells:

nucleus

organelles are not found in prokaryotic cells

mitochondria

chloroplasts

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Question 501 pts

Which of the following is a specialized components of the cell, is associated with the rough endoplasmic reticulum, and is responsible for making proteins.

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Question 511 pts

Proteins are sorted, modified, and packaged by the _____________ and later transported to the outside of the cell.

ribosomes

golgi bodies (golgi apparatus)

nucleus

mitochondria

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Question 521 pts

Dehydration synthesis is a process of linking two smaller subunits together to form a polymer. Which of the following statements below is true of dehydration synthesis?

Oxygen is consumed.

A water molecule is removed from the molecules.

A water molecule is added to the molecules

Carbon dioxide is given off.

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Question 531 pts

Proteins are made up of _________ held together by peptide bonds.

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Question 541 pts

Which of the following gives an amino acid its properties?

NH2

R Group or functional group

COOH

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Question 551 pts

The final three-dimensional shape of a protein that includes the bonding of two or more polypeptide chains is call its _____ structure.

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Question 561 pts

How do DNA and RNA differ?

all statements are differences between DNA and RNA.

DNA is double stranded while RNA is single stranded.

They have different sugars.

Thymine is present in DNA but not in RNA.

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Question 571 pts

Which of the following is a component of a DNA nucleotide?

phosphate

a nitrogen containing base

All are components of a nucleotide.

5-carbon sugar

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Question 581 pts

Cell membranes are made up of several different types of molecules. Select the membrane molecule below that is made up of a polar region and two non-polar fatty acid tails.

transmembrane proteins

carbohydrate chains

phospholipids

cell surface proteins

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Question 591 pts

Two organelles which are believed to have once been free-living bacterial cells are ____________ and ______________.

chloroplasts and mitochondria

golgi apparatus and endoplasmic reticulum

ribosomes and nucleolus

peroxisomes and lysosomes

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