Au Cell Biology - Exam 1

Front 1

A bacterium can divide every 20 minutes so it would take 44 hours for the weight of the bacteria to equal the weight of the earth. Why are we not overrun by bacteria? (1-4)

Back 1

The ability to divide quickly is only one factor in the survival of the species. Food is scarce so individuals have to compete. Natural selection chooses the mutants that find the most food.

Front 2

Why does mitochondria have an inner and outer membrane? (1-5)

Back 2

The outer membrane derived from the cell membrane of the eucaryotic cell. The inner from the aerobic bacterium. The cytosol contains the DNA from the ancestral bacterium.

Front 3

Why did eucaryotic cells evolve elaborate internal membrane systems that allow them to import substances from the outside. (1-6)

Back 3

Since they engulf food, they can feed on them efficiently. Bacteria can break down food externally but then they have to share other cells.

Front 4

What are the advantages and disadvantages of light and electron microscopy? (1-7)

Back 4

Light microscopy is much easier and simpler. The lower limit of resolution is 0.2 micrometers, 1000 times. Since light is non-destructive it is possible to view living cells. Electron microscopy is more complicated. Living cells cannot be observed. Resolution is 2 nanometers, 1 million times.

Front 5

Why is yeast a model organism for cancer research? (1-8)

Back 5

Yeast cells are much simpler than human cells and can be grown inexpensively in large quantities. The can also be modified genetically more easily than human cells. Cancer is problem in cell division so yeast can be used to better understand the processes involved.

Front 6

Cytosol

Back 6

The contents of the cytoplasm minus membrane-bound organelles.

Front 7

Cytoplasm

Back 7

Contents of the cell inside the cell membrane but outside the nucleus.

Front 8

Mitochondria

Back 8

Carries out oxidative phosphorylation and produces most of the ATP in eucaryotic cells.

Front 9

Nucleus

Back 9

The major organelle in eucaryotes. Contains chromosomes.

Front 10

Chloroplasts

Back 10

Organelle in plants that contains chlorophyll where photosynthesis takes place.

Front 11

Lysosomes

Back 11

Organelles containing digestive enzymes, has acidic pH.

Front 12

Chromosomes

Back 12

Composed of DNA and associated proteins.

Front 13

Golgi Apparatus

Back 13

Organelle that modifies and sorts lipids and proteins from the ER.

Front 14

Peroxisomes

Back 14

Uses oxygen to oxidize organic molecules. Contains enzymes that produce and degrade hydrogen peroxide.

Front 15

Plasma Membrane

Back 15

Phospholipid bilayer that surrounds the cell.

Front 16

Endoplasmic Reticulum

Back 16

Organelle where lipids are secreted and proteins are made.

Front 17

Cytoskeleton

Back 17

Protein filaments in the cytoplasm that gives cell shape and capacity for movement. Composed of actin filaments, microtubules and intermediate filaments.

Front 18

Name the three major classes of filaments and how they are used. (1-13)

Back 18

Actin filaments are involved in rapid movement such as the contraction of muscle. Intermediate filaments provide mechanical stability such as in the epidermis. Microtubules function as railroad tracks and are responsible for the separation of chromosomes during cell division.

Front 19

Name an advantage to being multicellular. (1-18)

Back 19

A plant can reach the soil with its roots for water and nutrients. While light and CO2 can be obtained by leaves. Also, protective structures can help the plant survive in harsh environments.

Front 20

Name some evidence for a common ancestor. (1-20)

Back 20

Many metabolic pathways are conserved from one cell to another. The compounds that make up nucleic acids and proteins are the same in all living cells.

Front 21

Exonuclease

Back 21

cleave the phosphodiester bond of dna at the end of the polynucelotide chain

Front 22

Endonuclease

Back 22

cleave the phosphodiester bond with a molecule of dna

Front 23

Hydrolase

Back 23

enzymes that catalyze a hydrolytic cleavage reaction

Front 24

Synthase

Back 24

enzymes that synthesize by condensing two molecules together

Front 25

Isomerase

Back 25

rearranges bonds within a single molecule

Front 26

Kinase

Back 26

catalyzes the addtion of phosphate groups to molecules

Front 27

Phosphatase

Back 27

hyrolytic removal of a phosphate group from a molecule

Front 28

ATPase

Back 28

Hydrolyze ATP

Front 29

Describe the rRNAs and what makes them.

Back 29

The large subunit is made up of 28S, 5.8S and 5S. The small subunit is 18S. RNA Polymerase I makes 28S, 5.8S and 18S, while RNA Plymerase III makes 5S.

Front 30

What are Ribozymes and give 4 examples.

Back 30

They are enzymes made out of RNA. Self-splicing RNA, snoRNA (processes rRNA), Spliceosomes, and rRNA peptide bond formation.

Front 31

Discuss: "The structure and function of a living cell are dictated by the laws of physics and chemistry"

Back 31

They cannot create energy de novo or build ordered structures withouth the expenditure of free energy. Cells always come from preexisting cells. Example plasma membrane cells form from existing membrane.

Front 32

What are the advantages of being multicellular.

Back 32

Cells can take on specialized functions. They can exploit food sources. Example plants can reach soil and light.

Front 33

List some evidence for a common ancestor.

Back 33

Metabolic pathways are conserved. The components of nucleic acids and proteins are the same.

Front 34

What is the advantage of condensation reactions.

Back 34

They are readily reversible by hydrolysis which is energetically favorable.

Front 35

How many electrons can be accommodated in the 1,2,3 electron shells.

Back 35

2,8,8

Front 36

Write the chemical formula for a peptide bond formation and hydrolysis

Back 36

page A:5

Front 37

T/F: Lipid bilayers are macromolecules that are made up of mostly phospholipid subunits.

Back 37

False: the forces between subunits are non-covalent so they are not macromolecules.

Front 38

What is the formula for determining how many different molecules can be made from amino acids.

Back 38

20^n where n is the number of amino acids in the sequence.

Front 39

Define amphipathic

Back 39

Amphipathic means that the molecule has a hydrophobic region and a hydrophillic region. It would form balls in the water or a film on the surface.

Front 40

Describe: nucleic acid, nucleotide, nucleoside.

Back 40

A nucleic acid is a string of nucleotides. A nucleotide is a phosphate, a five-carbon sugar, and a nitrogenous base. A nucleoside is just the sugar and the base.

Front 41

Describe the nucleotides.

Back 41

Adenine is a purine with two rings that bonds with the pyramidine Thymine by forming two hydrogen bonds. Cytosine is a pyramidine that forms three hydrogen bonds with Guanine, a purine.

Front 42

light energy + CO2 + H2O -> sugars + O2 + heat energy, would this reaction be catalyzed by a single enzyme. why is heat generated.

Back 42

This is the bottom line of a lot of other reactions that require many different enzymes. The second law says that when order is created, heat energy must be released.

Front 43

What is the difference between ΔG° and ΔG

Back 43

ΔG° is constant, ΔG is a affected by temp., pressure and [].

Front 44

Discuss phosphorylation and the binding of a nucleotide to protein.

Back 44

An advantage of nucleotide binding is that occurs very quickly. An advantage of phosphorylation is that it requires only one amino acid residue to bind rather than a specific binding site.

Front 45

T/F catalysis by some enzymes involve the formation of covalent bonds between a side chain and a substrate

Back 45

True

Front 46

T/F the specificity of an antibody is contained only in the loops of the light chain domain.

Back 46

False. light and heavy chains

Front 47

T/F affinity chromatography separates molecules according to their intrinsic charge

Back 47

False. is separates them according to their interaction with specific ligands

Front 48

How is the 5' cap formed and why?

Back 48

Phosphohydrolase removes the terminal phosphate group. Guanylyl transferase adds guanine residue in reverse orientation with 5'-5' linkage. Methyl groups added to guanine and nascent rna. It is called the methylguanosine cap and it keeps exonuclease from chewing the ends, aids in transportation out of the nucleus, plays an important role in translation.

Front 49

Name 3 differences between prokaryotic and eukaryotic mRNA.

Back 49

Eukaryotes have 5' cap, poly-a tail, and introns.

Front 50

RNA polymerase II creates what?

Back 50

mRNA and most snRNAs

Front 51

Draw out splicesosome complex

Back 51

U2AF bind and BBP bind to the A site. U1 binds downstream, U2 binds at the A site. U4/U6 U5 form spliceosome which is snRNAs and proteins.

Front 52

Draw out mRNA export

Back 52

Nuclear transport receptor binds to the middle, poly-a-binding protein binds to the end. Exits through the nuclear pore complex. Proteins return to nucleus. 5' cap exchanged for initiation factor.

Front 53

Conditions for standarized G

Back 53

1 atm, 25 degrees C, 1 M reactants, 55.6 M water, 7 pH

Front 54

Examples of activated carriers

Back 54

ATP, NADH, FADH2, NADPH (plants)

Front 55

Which is energetically favorable, condensation or hydrolysis

Back 55

Hydrolysis because it creates disorder

Front 56

What makes the a-helix

Back 56

N-H forms hydrogen bond at 4th C-O. This makes 3.6 amino acids per turn. Anything different is not alpha.

Front 57

Differences in DNA replication between prokaryotes and eukaryotes

Back 57

Prokaryotes
-circular DNA
-one origin
-no telomeres
Eukaryotes
-linear DNA
-multiple orgins
-Telomeres

Front 58

Four types of DNA repair

Back 58

Mismatch repair, double strand break repair, nucleotide excision repair, base excision repair