Biology: Ch.1- The Cell Flashcards
what are the four fundamentals tenants of cell theory?
- All living things are made of cells
- The cell is the basic fundamental unit of life
- All cells arise from other cells
- Genetic information is carried in the form of deoxyribonucleic acid (DNA) and is passed from parent to daughter cell
What is the function of the nucleus?
Stores genetic information and is the site of transcription
What is the function of the mitochondria
involved in ATP production and apoptosis
What is the function of the lysosomes
break down molecules ingested through endocytosis and cellular waste products
also involved in apoptosis
What is the function of the rough endoplasmic reticulum
synthesizes proteins destined for secretion
What is the function of the smooth ER
lipid synthesis and detoxification
What is the function of the Golgi apparatus
packages, modifies, and distributes cellular products
What is the function of the peroxisomes
break down very long chain fatty acids, synthesizes lipids and contribute to the pentose phosphate pathway
A child is diagnosed with an enzyme deficiency that prevents the production of hydrogen peroxide. What would be the likely outcome of such a deficiency?
Peroxisomes are dependent on hydrogen peroxide for their functions, so an enzyme deficiency that results in the inability to form hydrogen peroxide would likely result in an inability to digest long chain fatty acids. These fatty acids would build up in peroxisomes until most of the cellular contents were displaced by oversized peroxisomes, ultimately resulting in cell death
List three elements of the cytoskeleton
- Microfilaments
- Microtubules
- Intermediate filaments
What are the predominant proteins in microfilaments?
Actin
What are the predominant proteins in microtubules?
Tubulin
What are the predominant proteins in intermediate filaments?
differ by cell type- including keratin, desmin, vimentin and lamins
How to cytoskeletal structures of centrioles and flagella differ?
centrioles: 9 triplets of microtubules around a hollow center
Flagella: 9 doublets on on the outsides with two microtubules on the inside
Epithelial cells or connective tissue?: fibroblasts, which produce collagen in a number of organs
connective tissue
Epithelial cells or connective tissue?: endothelial cells, which line blood vessels
Epithelial cells
Epithelial cells or connective tissue?: alpha-cells, which produce glucagon in the pancreas
Epithelial cells
Epithelial cells or connective tissue?: osteoblasts, which produce osteoid, the material that hardens into bone
connective tissue
Epithelial cells or connective tissue?: chondroblasts, which produce cartilage
connective tissue
How are archaea similar to bacteria? How are they different from bacteria?
similar:
i. both are single celled organisms
ii. lack a nucleus or membrane bound organelles
iii. contain single circular xsome
iv. divide by binary fission or budding
v. overall share a similar structure
different:
i. start translation with methionine
ii. contain similar RNA polymerases
iii. associate their DNA with histones
What are the three common shapes of bacteria?
- spherical- cocci
- rod shaped- bacilli
- spiral shaped- spirilli
How do gram + and gram - bacteria differ?
Gram +: thick layer of peptidoglycan and lipoteichoic acid, contain no outer membrane
Gram -: thin layer of peptidoglycan and am outer membrane containing lipopolysaccharides and phospholipids
How eukaryotic and prokaryotic flagella differ?
euk flagella: contain microtubules composed of tubulin, organized in a 9+2 arrangement
prok flagella: made of flagellin and consist of a filament, a basal body and a hook
What are the three mxns of bacterial genetic recombination?
- Transformation
- Conjugation
- Transduction
What is transformation?
The acquisition of genetic material from the environment that can be integrated into the bacterial genome
What is conjugation?
The transfer of genetic material from one bacterium to another across a conjugation bridge- a plasmid can be transferred from F+ cells to the F- cells, or a portion of the genome can be transferred from an Hfr cell to the recipient
What is transduction?
The transfer of genetic material from one bacterium to another using a bacteriophage as a vector
what are the four phases of the bacterial growth curve and what happens in each phase?
- Lag phase: bacteria get used to environment; little growth during this time
- Exponential (log) phase: bacteria use available resources to multiply at an exponential rate
- Stationary phase: bacterial multiplication ceases as resources are used up
- Death phase: Bacteria die as resources become insufficient to support the colony
Why are viruses considered obligate intracellular parasites?
Viruses do not contain organelles, such as ribosomes; therefore, in order to reproduce and synthesize proteins, viruses must infect cells and hijack their cellular machinery
Coronavirus, which causes the common cold, is described as an enveloped, single stranded positive-sense RNA virus. What does this description indicate about the virus?
The description indicates that the virus contains an outer layer of phospholipids with an inner capsid. Within the capsid, there is a single-stranded RNA that can be immediately translated to protein by the ribosomes of the host cell
Briefly describe the pathway of retroviral nucleic acids from infection of a host cell to release of viral progeny
The nucleic acid enters as single stranded RNA, which undergoes reverse transcription (using reverse transcriptase) to form double stranded DNA. This DNA is transcribed to mRNA, which can be used to make structural proteins. This mRNA doubles as the viral genome for new virions. Once new virions are assembled from the structurl proteins and mRNA (ssRNA) genome, the virions can be released to infect other cells
What are the differences between the lytic and the lysogenic cycle?
in the lytic cycle: bacteriophages replicate in the host cell in extremely high numbers until the cell lyses and releases the virions
in the lysogenic cycle: the bacteriophage genome enters the host genome and replicates with the host cell as a provirus. At some point (after exposure to an environmental stimulus), the provirus leaves the host genome and can be used to synthesize new virions
How do prions cause disease?
Prions cause disease by triggering a change in the conformation of a protein from alpha helix to a beta pleated sheet. This reduces the solubility of the protein and makes it highly resistant to degradation
