BIOL1001 Lecture Notes - Lecture 19: Hydrophile, Choline, Amphiphile

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9 Aug 2016

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Phospholipids are major components of the plasma membrane, the outermost layer of animal cells. Like fats, they are composed of fatty acid chains attached to a glycerol backbone. Unlike triglycerides, which have three fatty acids, phospholipids have two fatty acids that help form a diacylglycerol. The third carbon of the glycerol backbone is also occupied by a modified phosphate group however, just a phosphate group attached to a diacylglycerol does not qualify as a phospholipid. This would be considered a phosphatidate, the precursor to phospholipids. To qualify as a phospholipid, the phosphate group should be modified by an alcohol. Phosphatidylcholine and phosphatidylserine are examples of two important phospholipids that are found in plasma membranes. A phospholipid is a molecule with two fatty acids and a modified phosphate group attached to a glycerol backbone. The phosphate may be modified by the addition of charged or polar chemical groups.

Related Questions

QUESTION 1

Ion diffusion across plasma membrane needs

		a concentration gradient across the membrane
		specific transporters
		ATP
		provide extra energy for the transport

2 points

QUESTION 2

There are four types of large biological molecules

2 points

QUESTION 3

Active transporters transport substances across cell membrane against ____________

2 points

QUESTION 4

Which of the following is a nonpolar amino acid?

	1.	Valine
	2.	Serine
	3.	Aspartic acid
	4.	Glutamic acid

2 points

QUESTION 5

Membrane potential of a cell is created by:

	1.	sodium ion concentration difference between inside and outside of the cell
	2.	a difference in protein concentration across the cell membrane
	3.	an electrical potential difference between the intracellular fluid and the surrounding extracellular fluid
	4.	a difference between the potassium concentration inside and outside of the cell

2 points

QUESTION 6

A mutation resulted in a change from a valine to a glutamic acid in a peptide sequence. This mutation will NOT change the protein folding

True

False

2 points

QUESTION 7

Ions can be transported across plasma membrane by

	1.	diffusion
	2.	No need of transporters
	3.	osmosis
	4.	active transport

2 points

QUESTION 8

Phospholipid is composed of

	1.	A glycerol backbone
	2.	One protein group
	3.	One carbohydrate group
	4.	Two fatty acid chains and one phosphate group

2 points

QUESTION 9

Prokaryotic cells and eukaryotic cells are similar in

	1.	Plasma membrane
	2.	nucleus
	3.	mechanism for protein translation
	4.	endoplasmic reticulum

2 points

QUESTION 10

Disulfide bonds are formed between two histidine residues

True

False

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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