PLB 300 Lecture Notes - Lecture 2: Lipid Bilayer, Nuclear Membrane, Robert Hooke

82 views7 pages

champagnebat172

30 Dec 2019

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Robert hooke invented the first microscope and noticed the microstructures of a cork. These were a part of the original form of cell theory. Dna, passed on from parent to daughter cell: 3 because they replicate by invading other organisms, 4 because they carry rna. Eukaryotic cells include a true nucleus enclosed in a membrane; prokaryotic cells do not contain a nucleus. Every eukaryotic cell membrane bound (i. e. , cell membrane) enclosing a semifluid cytosol (i. e. , intracellular fluid) in which the organelles are suspended. Linear dna is wound around organizing proteins called histones: histones are further wound into chromosomes, allowing for compartmentalization of dna transcription and rna translation, nucleolus: ribosomal rna (rrna) is created. Power plant of the cell has a dual layer membrane: outer layer: barrier between the cytosol and the inner environment. Inner layer: numerous folds known as cristae, contains the molecules/enzymes for the etc. If secretion occurs: secretory vesicles merges with cell membrane and contacts released via exocytosis.

Related Questions

Class 6: Viruses (and Cells, continued)

Making connections: viruses and microbes Match the cell biology concept (on page 1) with an important application of that concept (on page 2). Then answer the follow-up questions at the bottom of page 2.

Cell Biology concepts
1. Bacteria that cannot construct new cell wall material become fragile and break down.
2. During influenza infection, the viral enzyme neuraminidase is required to release new viruses from the host cell in which they were made. Once released, the new viruses can infect many additional cells.
3. Thermus aquaticus is a bacterium found in hot springs and can live at temperatures up to ~80Â°C (175Â°F). It has adapted so that its enzymes are most functional at the elevated temperatures, compared with many organismsâ enzymes that function best ~37Â°C (98Â°F).
4. Until the isolation and investigation of retroviruses, scientists thought that RNA could be copied from DNA, but DNA could not be copied from RNA. Research on this class of viruses led to an update to this âCentral Dogmaâ of biology.
5. Some bacteria have adapted, so that the enzymes involved in making cell wall materials have a slightly different shape and can no longer be bound by certain drugs.
6. Rhizobia are bacteria that colonize the roots of certain plants (legumes, including beans and peas). The host plant benefits from the prokaryotesâ ability to âfixâ nitrogen, converting N2 from the atmosphere into a form that is usable by the plant.
7. Many species of bacteria contain the enzyme cellulase. More than 10 billion such bacteria and other symbiotic microbes may be found in a single milliliter of material from inside the digestive system of ruminant mammals.
8. Fungi, including those that cause athleteâs foot, use ergosterol to maintain healthy membranes. Animal cells do not make ergosterol, they use a similar lipid â cholesterol.
9. During retrovirus infection, a DNA copy is made of the virusâs RNA genome. A cut is made in the host cellâs DNA and the DNA copy of the viral genome is pasted into the host chromosome by a viral enzyme called integrase.
10. Prokaryotic cells contain smaller ribosomes (â70Sâ ribosomes) than eukaryotic cells (â80Sâ ribosomes). Both types of ribosomes synthesize proteins, but the macromolecules they use to do it are somewhat different.

2
Applications
_______ Oseltamivir, also called Tamiflu, binds and inhibits the viral protein neuraminidase.
_______ Clotrimazole is a drug that is used to treat certain infections. It interferes with synthesis of ergosterol, a lipid involved in phospholipid membranes.
_______ Penicillin is a drug that interferes with synthesis of peptidoglycans (these are biological molecules that are part protein and part carbohydrate) that are present in certain cell walls.
_______ HIV is often treated with several drugs that inhibit different parts of the viral replicative cycle. Raltegravir is an example of a drug that interferes with the integration of viral genes into the host cellâs chromosome.
_______ Cows, like other vertebrates, lack the ability to breakdown cellulose. Yet they are able to live on a diet of grass and other vegetation high in cellulose.
_______ Enzymes isolated from extremophiles have been very useful in laboratory research. For example, Taq polymerase facilitates PCR, a revolutionary technique for production of DNAs of particular sequences, which requires cycling reactions through high temperatures.
_______ Plants and animals require nitrogen to make biological macromolecules, however theyâre unable to convert atmospheric nitrogen (N2) into a biologically useful form.
_______ Azithromycin is a drug that binds to 70S ribosomes and blocks synthesis of any new proteins.
_______ Methicillin-Resistant Staphylococcus aureus (MRSA) can cause life-threatening infections of the skin and bloodstream. One of the reasons MRSA infections are so serious is that they are resistant to treatment by many antibiotics, including methicillin and penicillin.
_______ The enzyme reverse transcriptase, isolated from retroviruses, is an important tool in molecular biology research. Scientists interested in learning what genes are turned on in particular cells use it to make DNA copies of RNAs they are studying (The DNA copies are useful because they are more stable).

When you have completed the matching activity, answer these follow-up questions:
â¢ What types of infections can be treated with the following drugs?
o Penicillin
o Clotrimazole
o Azithromycin
o Tamiflu
o Raltegravir
â¢ Why are these drugs (above) safe for you to take? That is, why donât they kill your cells?
â¢ Cancer cells are your own human cells that have become deregulated so that they divide and pile up in an uncontrolled way. Many chemotherapy drugs treat cancer by interfering with cell division and other cell processes.
o Why are there so many more side effects for individuals undergoing chemotherapy than for individuals taking antibiotics?

__________ are fairly small organelles that provide a safe place within the cell to carry out certain biochemical reactions that generate harmful, highly reactive oxygen species. These chemicals are both generated and broken down in the same location.

Lysosomes

Endosomes

Peroxisomes

Nucleosomes

Biologists cannot possibly study all living species. Instead, they try to understand cell behavior by studying a select subset of them. Which of the following characteristics are useful in an organism chosen for use as a model in laboratory studies?

rapid rate of reproduction

all of the above

ability to grow under controlled conditions

amenability to genetic manipulation

By definition, prokaryotic cells do not possess __________.

ribosomes.

a nucleus.

membrane bilayers.

replication machinery.

Cell biologists employ targeted fluorescent dyes or modified fluorescent proteins in both standard fluorescence microscopy and confocal microscopy to observe specific details in the cell. Even though fluorescence permits better visualization, the resolving power is essentially the same as that of a standard light microscope because the resolving power of a microscope is limited by the __________ of light.

intensity

absorption

wavelength

filtering

Choose the phrase that best completes this sentence: Microtubules ____________ and are required to pull duplicated chromosomes to opposite poles of dividing cells.

generate contractile forces

can rapidly reorganize

are found in especially large numbers in muscle cells

are intermediate in thickness

Despite the differences between eukaryotic and prokaryotic cells, prokaryotes have proteins that are distantly related to eukaryotic actin filaments and microtubules. What is likely to be the most ancient function of the cytoskeleton?

cell division

cell motility

vesicle transport

membrane support

DNA and RNA are different types of nucleic acid polymer. Which of the following is true of DNA but not true of RNA?

It contains thymine.

It has 5'-to-3' directionality.

It is single-stranded.

It contains uracil.

Double covalent bonds are both shorter and stronger than single covalent bonds, but they also limit the geometry of the molecule because they ____________________.

prevent additional bonds from being formed with the bonded atoms.

limit the rotation of the bonded atoms.

create a new arrangement of electron shells.

change the reactivity of the bonded atoms.

Drosophila melanogaster is a/an __________. This type of animal is the most abundant of all animal species, making it an appropriate choice as an experimental model.

mammal

amphibian

bird

insect

10.

If the isotope 32S has 16 protons and 16 neutrons, how many protons, neutrons, and electrons will the isotope 35S have, respectively?

16, 19, 17

16, 19, 15

16, 19, 16

16, 20, 15

11.

Living systems are incredibly diverse in size, shape, environment, and behavior. It is estimated that there are between 10 million and 100 million different species. Despite this wide variety of organisms, it remains difficult to define what it means to say something is alive. Which of the following can be described as the smallest living unit?

cell

organelle

protein

DNA

12.

Macromolecules in the cell can often interact transiently as a result of noncovalent interactions. These weak interactions also produce stable, highly specific interactions between molecules. Which of the factors below is the most significant in determining whether the interaction will be transient or stable?

the concentration of each molecule

the size of each molecule

surface complementarity between molecules

the rate of synthesis

13.

Many of the mechanisms that cells use for maintenance and reproduction were first studied at the molecular level in bacteria. Which bacterial species had a central role in advancing the field of molecular biology?

E. coli

S. pombe

C. elegans

D. melanogaster

14.

Many types of cells have stores of lipids in their cytoplasm, usually seen as fat droplets. What is the lipid most commonly found in these droplets?

cholesterol

isoprene

triacylglycerol

palmitic acid

15.

Mitochondria contain their own genome, are able to duplicate, and actually divide on a different time line from the rest of the cell. Nevertheless, mitochondria cannot function for long when isolated from the cell because they are __________________.

anaerobes.

viruses.

parasites.

endosymbionts.

16.

Mitochondria perform cellular respiration, a process that uses oxygen, generates carbon dioxide, and produces chemical energy for the cell. Which answer below indicates a correct pairing of material âburnedâ and the form of energy produced during cellular respiration?

17.

Polar covalent bonds are formed when the electrons in the bond are not shared equally between the two nuclei. Which one of these molecules contains polar bonds?

Please choose the best answer in these mcqs:

1. Cells carry out different metabolic reactions, in differentcompartments (= different enclosed organelles of the cell). Whichof the following are the reasons for this?

A) Protect the metabolism from unwanted environmentalfactors

B) Enclosure enables maintaining high concentrations of thecomponents without letting them diffuse away

C) More concentrated substances can react more readily, withincreased efficiency

D) All of the above

E) Only a and b

2.Which of the following developed during the evolution ofeukaryotic cells from prokaryotic cells?

A) DNA

B) the cell membrane

C) nuclear membranes to form nucleus

D) ribosomes

E) proteins

3. Which three cellular components are present in bothprokaryotes and eukaryotes?

A) ribosomes, chloroplasts, mitochondria

B) nucleus, ribosomes, RNA

C) RNA, DNA, ribosomes

D) endoplasmic reticulum, DNA, RNA

E) mitochondria, DNA, RNA

4.Phylogeny is

A) the science of biological classification based onmorphological features of organisms

B) the science of biological classification based on theevolutionary relationships between organisms.

C) the science of biological classification based onreproductive strategies.

D) the branch of science that studies phyllopods.

E) none of the above

5.Which of the following is False regarding mutations?

A) They are small changes in an individualâs geneticmaterial

B) All mutations are bad and cause diseases

C) Mutations that increases the chances of an individualorganism increases the possibility that this mutation is passed onto next generations

D) Mutations that are deleterious (damaging to the organism)tend to end with the organismâs death

6.Which of the following is NOT true about evolution theory?

A) It proceeds through random changes, that affect the abilityof the organism to reproduce and survive under existingenvironmental circumstances

B) Variations in individual organisms is better for survival andadaptation to changes, than being homogenous

C) All the changes in an organism are new, they were notdependent on preexisting features

D) Organisms continue to evolve; evolution has not stopped

7.In thermodynamics, the reaction (or organism or the materialwe are studying) of interest is called:

a) State

b) Universe

c) Matter

d) Energy

whitewildebeest237

PLB 300 Lecture Notes - Lecture 2: Lipid Bilayer, Nuclear Membrane, Robert Hooke

Document Summary

Get access

Related Documents

PLB 300 Lecture Notes - Lecture 4: Restriction Point, Dna Replication, P53

PLB 300 Lecture Notes - Lecture 16: Cyanobacteria, Heliobacteria, Bacteriochlorophyll

BIOL 22000 Lecture Notes - Lecture 1: Methionine, Leptospira Interrogans, Vitamin K

Related Questions