- Found in the cell region called centrosome. - Organizing center for microtubules - Structured as nine triplets of microtubules with hollow center - Migrate to opposite poles of dividing cell during mitosis. Microtubules emanating from centrioles attach to chromosomes via kinetochores

1: The Cell Flashcards by Elizabeth Blackmore

What are the four basic tenets of cell theory?

1) All living things are composed of cells
2) Cell is the basic functional unit of life
3) Cells arise only from pre-existing cells
4) Cells pass on genetic information in form of nucleic acids

How well did you know this?

Not at all

Perfectly

Name the eukaroytic organelles

Nucleus, nucleolus, mitochondria, lysosomes, endoplasmic reticulum, golgi apparatus, peroxisomes

How well did you know this?

Not at all

Perfectly

What is a peroxisome?

Contain hydrogen peroxide.
Break down very long chain fatty acids through beta-oxidation.
Also participate in phospholipid synthesis and the pentose phosphate pathway

How well did you know this?

Not at all

Perfectly

What are the functions of the cytoskeleton?

Provides stability and rigidity to cell structure

- provides transport pathways within cell

How well did you know this?

Not at all

Perfectly

What are the three components of the cytoskeleton?

Microfilaments
Microtubules
Intermediate filaments

How well did you know this?

Not at all

Perfectly

What are cytoskeletal microfilaments?

solid polymerized rods of actin

- organized into bundles/networks

How well did you know this?

Not at all

Perfectly

What are the functions of cytoskeletal microfilaments?

PROTECTION: resistant to compression and fracture => protect cell
MOVEMENT: use ATP to generate force through interaction with myosin => muscle contraction
REPRODUCTION: during cytokinesis, ring of microfilaments at site of division form cleavage furrow. As actin filaments contract, cell divides.

How well did you know this?

Not at all

Perfectly

What are microtubules? What is their function?

Hollow polymers of tubular proteins

- Radiate through cell, providing pathways for motor proteins (kinesin, dynein) to carry vesicles

How well did you know this?

Not at all

Perfectly

Discuss some specialized microtubules and their functions

CILIA, FLAGELLA - both microtubule projections

In eukaryotes, both have 9-2 structure [FINISH THIS]

How well did you know this?

Not at all

Perfectly

What are centrioles?

Found in the cell region called centrosome.
Organizing center for microtubules
Structured as nine triplets of microtubules with hollow center
Migrate to opposite poles of dividing cell during mitosis. Microtubules emanating from centrioles attach to chromosomes via kinetochores

How well did you know this?

Not at all

Perfectly

What are intermediate filaments?

Group of filamentous proteins: keratin, desmin, vimentin, lamins

Functions: cell-cell adhesion, cytoskeleton integrity, cell rigidity, anchoring organelles

How well did you know this?

Not at all

Perfectly

What are the four animal tissue types?

Nervous, muscle, epithelial, connective

How well did you know this?

Not at all

Perfectly

Describe epithelial cells

Covers body; lines cavities
Protects against invasion, desiccation
cells tightly joined to each other and underlying connective tissue with a basement membrane

How well did you know this?

Not at all

Perfectly

What is the parenchyma of an organ?

The functional parts!

How well did you know this?

Not at all

Perfectly

What are some examples of epithelial cells serving as the parenchyma of an organ?

Nephrons of kidney
Hepatocytes of liver
Acid-producing cells of stomach

How well did you know this?

Not at all

Perfectly

What are the different classes of epithelial cell?

Simple epitheila - one layer
Stratified epithelia - multiple layers
Pseudostratified epithelia - appear to have multiple layers but really just difference in cell height.

How well did you know this?

Not at all

Perfectly

What are the different shapes of epithelial cell?

Cuboidal, columnar, squamous (flat, scale-like)

What is a stroma?

Support structure

What are examples of connective tissues?

Bone, cartilage, tendons, adipose tissue, blood

What produces the extracellular matrix?

Produced by collagen/elastin secreted by connective cells

In what region of a prokaryote is DNA found?

The nucleoid region

How are archaea similar to bacteria and eukaryotes?

To eukaryotes: start translation with methionine, similar RNA polymerases, histones

To bacteria: single circular chromosome, division by binary fission/budding

What are the main shapes of bacteria?

Cocci - spherical
Bacilli - rod
Spirilli - spiral

What are the four aerobic metabolic bacterial categories?

Obligate aerobes
Obligate anaerobes
Facultative aerobes
Aerotolerant anaerobes

What is the bacterial envelope made from?

Cell wall - outer barrier Cell membrane , composed of phospholipids (Cell wall and cell membrane together known as envelope)

Discuss differences in gram positive/gram negative bacterial cell walls

Gram positive - thick layer of peptidoglycan; also lipoteichoic acid (causes immune inflammatory response) Gram negative - v thin layer of peptidoglycan, separated from membrane by periplasmic space. Outer membrane contains phospholipids and lipopolysaccharide (causes much stronger immune inflammatory response)

Discuss the structure of bacterial flagella

Filament - long, hollow, helical structure made of flagellin Basal body - anchors flagellum to cell, motor, rotates up to 300hz! Hook - connects the two

Discuss the differences between prokaryotic and eukaryotic ribosomes

``` Prokaryotic = 30S Eurkaryotic = 40S and 60S ```

Do prokaryotes have a cytoskeleton?

Yes, but it's much less complex than eukaryotic cytoskeletons!

What do we call a plasmid that can integrate into the bacterial genome?

An episome

What are transposons?

Genetic elements that insert or remove themselves from the genome

What are the phases of bacterial growth?

Lag phase - bacteria adapt to local conditions Log phase (exponential phase) - rapid growth Stationary phase Death phase

What is a virus protein coat called?

Capsid, made of capsomeres

What is a virion?

An individual virus particle

What is the function of the tail sheath and tail fibers of a bacteriophage?

Sheath - injects nucleic acids | fibers - attaches/recognizes bacteria

What are positive sense and negative sense ssRNA viruses?

Positive sense - ssRNA can directly be translated by host cell Negative sense - complementary RNA strand must first be synthesized by RNA replicase

What is a retrovirus?

ssRNA virus, to which complementary DNA is made using reverse transcriptase. DNA then integrated into genome

Name three ways a virion can leave a cell

- Virus initiates cell death - Cell lyses from large number of virions - Virion extrudes from cell, keeping host cell alive

What is a provirus?

Same as a prophage - virus integrated into host genome during lytic cycle

Why may a bacterium tolerate a phage?

- Infection with one phage = less likely infection with other - Some phages are innocuous

What is a prion? How do they cause disease?

- Infectious protein - May trigger misfolding of nearby proteins -- reducing solubility and ability of cell to remove protein - Aggregates reduce cell function Examples: mad cow, familial fatal insomnia

What is a viroid?

- Very short ssRNA, usually infects plants - Bind to many RNA sequences, silence genes in plant genome - Human examples: Hep D