The Cell Flashcards
Cell Theory
(1) All living things are composed of cells
(2) The cell is the basic functional unit
(3) Cells arise only from preexisiting cells
(4) Cells carry DNA that is passed down
DNA —> _______ —-> ________——>______
DNA —> genes —-> histones——> chromosomes
What is the function of the nucleus?
stores genetic information and transcription occurs here
What is the function of the mitochondria?
ATP production and apoptosis
What makes the mitochondria unique from other organelles?
can replicate independently of the cell by binary fission
What is the function of lysosomes?
contain hydrolytic enzymes that are capable of breaking down many different substrates
What is the function of endosomes?
to transport, package, and sort cell material travelling to and from the membrane
What is the function of the rough ER?
contains ribosomes which permit the translation of proteins destined for secretion directly to the lumen
What is the function of the smooth ER?
utilized for lipid synthesis and detoxification of certain drugs and poisons, also helps transport proteins the Golgi apparatus
What is the function of the Golgi apparatus?
contain stacked of membrane bound sacs which can modify cellular products by adding carbohydrates, phosphates, sulfates, signal sequences and then packages them
How do cellular products get from the Smooth ER to the GA?
vesicles
What is the function of peroxisomes?
to break down very long fatty acid chains through beta-oxidation, synthesis phosopholipids
What is the function of the cytoskeleton?
provides structure and conduit for transport
What is the cytoskeleton made of?
microfilaments, microtubules, and intermediate filaments
What is the function of microfilaments?
made of actin filaments which provide structure and help with movement through muscle contraction
What is the function of microtubules?
hollow polymers of tubulin proteins and provide pathways for motor proteins (kinesin, dynein), “conveyor belt”, structure
What are cilia and flagella composed of and how it structured?
microtubules arrranged in a ring with 9 on the outside of the ring and 2 microtubules in the center
What is the difference between cilia and flagella?
the former help move materials along the surface of the cells and the latter helps move the cell itself
What is the function of centrioles?
“organizing centers for microtubules” of 9 triplets of microtubules with a hollow center. They play a role in mitotic division
What is the function of intermediate filaments?
involved in cell to cell adhesion, maintenance/structure of cytoskeleton, anchor other organelles
What are examples of intermediate filaments?
keratin, desmin, vimentin, and lamins
What are the different types of tissues?
epithelial, connective tissue, muscle and nervous tissue
What is the function of epithelial tissues?
cover the body and line cavitites/organs, acts are protection against pathogens. can be involved in absorption, secretion and sensation, contribute to parenchyma
What is parenchyma?
the functional parts of the organ
Examples of epithelial tissue
nephrons, hepatocytes,
What are the different types of epithelial cells based on layers?
simple- one layer of cells
stratified - multiple layers of cells
pseudostratified - appear to have multiple layers due to height differences but are just one
What are the different types of epithelial cells based on shape?
cuboidal - cube shaped
columnar - long and thin
squamous - flat, scalelike
What is the function of connective tissue?
tissue that supports the body and provides a framework for the epithelial cells to carry out functions, contribute to the stroma
What is stroma?
support structure
Examples of connective tissue
bone, cartilage, tendons, ligaments, adipose tissue, and blood
If the cells of a tissue produce collagen, what kind of tissue type is it?
connective
What are the three domains of life?
Archaea, Bacteria and Eukarya
What is one thing that makes Archaea noticeably unique?
their ability to use alternative sources of energy
What are the similarities between bacteria and archaea?
Both have similar physical structures, contain singular circular chromosomes, and divide by binary fission
What are the similarities between archaea and eukarya?
both start translation with methionine, contain similar RNA pol, and associate DNA with histones
What are the shapes of bacteria?
cocci - spherical
bacilli - rod-shaped
spirilli = spiral shaped
Bacteria that require oxygen for metabolism are called
obligate aerobes
Bacteria that do not require oxygen are called
anaerobes
What are the different types of anaerobes?
Obligate anaerobes - cannot be in environment with oxygen or will die
Facultative anaerobes - can use both oxygen or not
Aerotolerant anaerobes - can’t use oxygen but not harmed by it
What are the characteristics of a gram positive cell wall?
thick peptidoglycan layer, contains lipotechoic acid
What are the characteristics of a gram negative cell wall?
very thin with small amounts of peptidoglycan, contains periplasmic space that separates peptidoglycan from cell membrane. ALSO HAVE outer membranes (phospholipids, lipopolysccharides)
What is peptidoglycan?
a polymeric substance made from amino acids and sugars
Are gram negative or gram positive more susceptible to antibiotics like penicillin and why?
these antibiotics have a enzyme that targets the crosslinking of peptidoglycan that is not protected by an outer membrane in gram positive like it is gram negative
What is chemotaxis?
the ability of a cell to detect chemical stimuli and move toward or away from them
What is the structure of the bacteria flagella?
Filament - hollow, helical structure composed of flagellin
Basal body - complex structure that anchors the flagellum to the cytoplasmic membrane and acts as the motor
Hook - connects the filament to the basal body
What is the difference between bacterial and eukaryotic flagella?
the former is made of a filament, basal body and hook while the latter is made of microtubules arranged in a 9 + 2 arrangement
What are episomes?
a type of plasmids that are capable of integrating into the genome of the bacterium
What is transformation?
integration of foreign genetic material into the host genome, normally when bacteria take up genetic material from environment
What is conjugation?
bacterial form of mating (sexual reproduction). A conjugation bridge is formed and the transfer is unidirectional. The donor is considered male and recipient female.
How is a conjugation bridge formed?
The bridge is made of appendages called sex pili on the male donor. In order to form this bridge, they must have plasmids with F factors.
What is an F factor and how does it work?
A fertility (F) factor is a type of sex factor found encoded on plasmids that by having it, the host cell to form the sex pili to make the conjugation bridge. only cells with this F factor can do this. So during conjugation, the plasmid is replicated and passed to the recipient cell, including the F factor, and thus turning that cell from F- to F+
What are Hfr cells?
Hfr stands for high frequency recombination and refers to cells that have undergone conjugation and had the plasmid transferred
What is transduction?
the process of exchanging genetic information from one bacteria to another through viruses
What is the name of a virus that specifically infects bacteria?
bacteriophage
What are transposons?
genetic elements capable of inserting and removing themselves from the genome
What are the different phases of bacterial growth when placed in a new environment?
Lag phase - bacteria are adapting to the new environment so very low, flat growth
Exponential/log phase - rate of division increases which causes an exponential increase
Stationary phase - reduction of resources slows reproduction
Death phase - after all the resources are depleted, the bacteria die off
What is the structure of viruses?
they contain genetic material, a protein coat (capsid), and sometimes an envelope containing lipids
What are the characteristics of genetic material in viruses?
Varies widely - circular, linear, singel or double stranded, DNA or DNA
Why are viruses unable to replicate independent of a host cell?
they lack ribosomes so they can’t carry out protein synthesis
What are virions?
viral progeny
How do bacteriaphages differ from other viruses?
they don’t enter the cell, only inject genetic material, they also have a tail sheath and tail fibers
What do tail sheath and tail fibers do?
tail sheath - act like a syringe, injecting genetic material into a bacterium
tail fibers - help the bacteriophage recognize and connect to the correct host cell
What are retroviruses?
enveloped, single-stranded RNA viruses in the family Retroviridae. These viruses contain an enzyme called reverse transcriptase which translates RNA to DNA and then gets integrated into the host cells genome and then gets automatically repliacated from here on out
What is an example of a retrovirus?
HIV
What are the two bacteriophage life cycles?
lytic and lysogenic cycles
What is the lytic cycle?
when the virus maximizes the cell’s machinery with little regard for the survival of the cell and then the cell lyses and the virions go on to infect other bacteria
What is the lysogenic cycle?
When the cell is not lysed, the virus becomes a provirus/prophage and integrates into the host genome and is able to replicate with the host bacteria. It can be pushed out the the host genome for environemntal reasons or otherwise and no longer replicates with the host and becomes part of the lytic cycle
What are prions?
infectious proteins that cause the misfolding of proteins from alpha-helical structure and beta-pleated sheet. This makes it hard to degrade the protein and therefore they build up in the cells
Examples of diseases caused by prions
bovine spogiform encephalopathy, Creutzfeldt-Jakob disease, and familial fatal insomnia
What are viroids?
small pathogens (short circular single-stranded RNA). They bind to large number of RNA sequences and silence genes in the plant genome
