Chapter 1: The Fundamental Units of Life

Question 1

What is Cell Theory?

Answer 1

All existing cells come from preexisting cells

Question 2

What is the main function of Peroxisomes?

Answer 2

Remove hydrogen peroxide from cells

Question 3

What is the main function of cytoskeletons?

Answer 3

protein filaments that Helps cells move and keep their shape, and facilitates organelle movement.

Question 4

What’s the major advantage of electron microscopy?

Question 5

What’s the major function of the Golgi Apparatus?

Answer 5

-Synthesis of some cell wall polysaccharides in plants

• Modification of secreted proteins

Question 6

Which of the following is NOT a function of the Golgi apparatus?

Answer 6

Synthesis of the majority of membrane phospholipids

Question 7

If you wanted to study the detailed internal membrane structure of a chloroplast, what kind of microscopy would be most appropriate?

Answer 7

Electron

Question 8

Animal cells contain mitochondria whereas plant cells do not - instead they have chloroplasts.

Answer 8

False

Question 9

What do eukaryotic cells have that prokaryotes lack?

Answer 9

a nucleus and membrane-bound organelles

Question 10

Oxidation reactions

Answer 10

are always accompanied by a reduction reaction

Question 11

Which four elements make up 96% of the weight of living organisms?

Answer 11

carbon, hydrogen, nitrogen, and oxygen

Question 12

Atoms form covalent bonds with each other by

Answer 12

sharing electrons

Question 13

On the basis of weight, which is most abundant in a living bacterial cell?

Answer 13

Water

Question 14

In water, hydrogen bonds can form between which of the following?

Answer 14

a hydrogen atom of one water molecule and an oxygen atom of another

Question 15

The reaction amino acids → polypeptide is an example of a spontaneous reaction

Answer 15

False

Question 16

A condensation reaction involves the cleavage of a covalent bond by the addition of a water molecule.

Answer 16

False

Question 17

A hydrolysis reaction involves the cleavage of a covalent bond by the addition of a water molecule.

Answer 17

True

Question 18

Cells contains the following four major families of small organic molecules: sugars, fatty acids, amino acids, and nucleotides.

Answer 18

True

Question 19

For a reaction to occur spontaneously..

Answer 19

• Free energy must be released
• Products have a lower energy than reactants
• The reaction is energetically favorable
• ∆G is negative

Question 20

Consider the following peptide: Met-Ile-Leu-Ala-Phe-Ile-Val-Leu
Overall, this peptide is likely to be

Answer 20

Hydrophobic and uncharged

Why? Because the peptides were all nonpolar amino acids. Nonpolar means they are hydrophobic and they had no charge.

Question 21

Which of the following molecules is likely to be amphipathic?

Answer 21

fatty acid

Question 22

Hydrogen bonds can only form between atoms of a polypeptide backbone, not between side chains.

Answer 22

False

Question 23

By what mechanism(s) can an enzyme lower the reaction’s activation energy?

• Positioning of substrates to favor the reaction
• Straining bonds within the bound substrate
• Rearrangement of electrons in the substrate
• Formation of a covalent bond between substrate and enzyme
• All of the above

Answer 23

All of the above

Question 24

An α-helix is held together by

Answer 24

hydrogen bonds between atoms in the polypeptide backbone

Question 25

Which technique would be most appropriate for the purification of a protein based on its charge?

Answer 25

ion exchange chromatography

Question 26

Regulation of proteins typically involves a conformational change in the protein structure.

Answer 26

True

Question 27

A protein phosphatase adds a phosphate group to a protein to regulate its activity.

Answer 27

False

Question 28

Allosteric regulation of enzymes requires binding of a regulatory molecule to the active site.

Answer 28

False

Question 29

In feedback inhibition, an enzyme acting early in a reaction pathway is inhibited by a late product of that pathway.

Answer 29

True

Question 30

What's referred to as the Central Dogma?

Answer 30

The flow of information in a cell: DNA-->RNA-->PROTEIN

Question 31

What is the major advantage and disadvantage of light microscopy?

Answer 31

Advantages: Can distinguish cell structures Disadvantages: Light, the wavelengths, limits the fineness of details.

Question 32

What is the major advantage and disadvantage of electron microscopy?

Answer 32

Advantages: Allowed us to see the finest of details on cells, such as the structures of the endoplasmic reticulum. Disadvantages: The process of preparing samples can't look at living cells.

Question 33

What evidence supports the endosymbiotic origins of mitochondria and chloroplasts?

Answer 33

mitochondria—the organelles that generate energy in eukaryotic cells—are thought to have evolved from aerobic bacteria that took to living inside the anaerobic ancestors of today’s eukaryotic cells. chloroplasts—have evolved from photosynthetic bacteria that long ago found a home inside the cytoplasm of a plant-cell ancestor. aerobic eukaryotic cell

Question 34

How prokaryotic and eukaryotic cells are defined?

Answer 34

Prokaryotes: rod, corkscrewed and spherical shaped, few micrometers long; have a tough protective cell wall surrounding plasma membrane. Single celled organisms contains: cytoplasm and DNA ex. bacteria and archaea Eukaryotes: plants animals and fungi are formed from eukaryotes . Contains nucleus that stores DNA inside a nuclear envelope

Question 35

What’s the major function of mitochondria?

Answer 35

harness the energy from the oxidation of food molecules, such as sugars, to produce adenosine triphosphate, or ATP consumes oxygen and releases CO2 in the course of this activity, the entire process is called cell respiration—essentially, breathing at the level of a cell.

Question 36

What’s the major function of chloroplasts?

Answer 36

found in the cells of plants and algae, but not in the cells of animals or fungi. carry out photosynthesis—trapping the energy of sunlight in their chlorophyll molecules and using this energy to drive the manufacture of energy-rich sugar molecules. In the process, they release oxygen as a molecular by-product.

Question 37

What’s the major function of the endoplasmic reticulum?

Answer 37

site where most cell-membrane components, as well as materials destined for export from the cell secrets proteins(ribosomes translate RNA into protein)

Question 38

What is the major function of peroxisomes?

Question 39

Why do scientists study model organisms?

Answer 39

biologists have become dedicated to studying a few chosen species, pooling their knowledge to gain a deeper understanding than could be achieved if their efforts were spread over many different species.