Cell Bio Lecture 1 Flashcards
list the 6 main elements of life
- carbon
- oxygen
- hydrogen
- nitrogen
- phosphorous
- sulfur
what is the most common element of life? where is it found? (2)
hydrogen; found in air and as a component of water
what main element is the backbone of most molecules?
carbon
what main element is a component of amino acids and air?
nitrogen
what main element is highly reactive and a component of RNA, DNA, ATP, and phospholipids?
phosporous
what main element is odoriferous, a component of amino acids, vitamins, keratin, and antibodies?
sulfur
what are the 2 most important trace elements for life? say why
- calcium: important second messenger and critical for bone development
- iron: important in RBCs
what are the 4 macromolecules?
- carbohydrates
- proteins
- lipids
- nucleic acids
what is the ratio of elements in carbohydrates?
1:2:1 carbon:hydrogen:oxygen
what are the 3 kinds of carbohydrates?
- monosaccharides
- disaccharides
- polysaccharides
what macromolecule comprises 50% of a cell’s dry weight?
protein
describe the basic structure of proteins
the amino acid, which is composed of an alpha carbon, an amino group, a carboxyl group, and an R group
what are lipids composed of? describe structure
fatty acids; with a polar hydrophilic group and a nonpolar hydrophobic group
describe the structure of nucleic acids
composed of monomeric nucleotides with a 5-carbon sugar, a phosphate group, and a nitrogenous base
what is the sugar in RNA?
ribose
what is the sugar in DNA?
deoxyribose
can mature RBCs divide? why or why not?
nope; no nucleus
why do we care about cells in terms of disease?
disease starts at a cellular level, then affects multiple cells (tissues), then multiple tissues (organs), then health of an animal
contrast eukaryotic cells to prokarytic cells
- eukaryotic cells have a nucleus, prokaryotes don’t
- eukaryote organelles are membrane-bound; prokaryote organelles have no membrane of their own
- eukaryotic DNA is linear, has histones, and is capped with mRNAs while prokaryotic DNA is circular, has no histones (is naked), and is not capped with mRNAs
what is the purpose of the histones in eukaryotic DNA?
keeps linear DNA from tangling and getting damaged
what is the purpose of eukaryotic DNA being capped with mRNA?
stability
how do eukaryotic cells divide?
mitosis and meiosis
how do prokaryotic cells divide?
binary fission
describe the cell plasma membrane
a semi-permeable phospholipid bilayer that serves as a barrier against substances harmful to the cell and a portal for nutrients, cell products, and waste transfer
what is another function of the cell plasma membrane and how does it accomplish this?
facilitates cell identity, attachment, activation, and communication via special protein structures on the surface
what binds to the receptors on the cell plasma membrane?
ligands
what are the 2 types of ligands?
- stimulating ligands, or agonists
- inhibitory ligands, or antagonists
what is the nucleus?
a membrane bound organelle in all eukaryotic cells that contains the majority of the cell’s genetic material
what is the role of the nucleus?
important in cell growth and metabolism, protein synthesis, and cell division
describe the membrane of the nucleus
porous to allow transcription factors through
describe actin filaments and what they are responsible for; where are they located?
a major component of the cytoskeleton; responsible for cellular integrity and cellular movement; in cytoplasm
describe microtubules and what they are responsible for
comprised of two subunits; are rigid hollow rods that play a role in chromosome movement during mitosis and organelle movement in the cytoplasm
describe the golgi and what they are responsible for
a series of flattened membrane organelles involved in protein glycosylation and packaging of secretory proteins
what side of the golgi faces the membrane? what side is closer to the ER?
the cis face faces the membrane while the trans face is closer to the ER
describe ribosomes
small bead-like structures with a large and small subunit comprised of RNA and protein
where is RNA located?
originates in the nucleus, then trafficked to the cytoplasm or bound to rough ER
what do ribosomes do?
read genetic code in mRNA to generate amino acids to build proteins
describe rough endoplasmic reticulum and what responsible for
flattened membrane organelles associated with ribosomes; involved in the synthesis of secretory and integral membrane proteins within the cytoplasm
what is smooth endoplasmic reticulum responsible for? where located?
associated with the synthesis and storage of lipids; near the nucleus
describe the mitochondria
a membrane bound organelle with smooth outer and folded inner membranes (POWERHOUSE OF THE MOTHERFUCKIN CELL)
what is mitochondria responsible for (3)
- oxidative phosphorylation of ADP to form ATP
- calcium storage site
- plays a role in apoptosis
what super unique thing does mitochondria have compared to other organelles?
a small segment of mitochondrial DNA (mtDNA)
where are high concentrations of mitochondria found? (2)
in muscle and liver cells
describe centrosome/centriole structure
composed of two barrel shaped clusters of microtubules called centrioles; centrioles are cylinders that act as an anchor for microtubules
what is the primary role of the centrosome (made up of centrioles)
facilitate cell division by pulling sister chromatids apart during mitosis and meiosis
what is a secondary role of centrosomes?
mediate cell membrane shape change during phagocytosis
what is the lysosome?
biodigester! a membrane bound organelle that appears in the cell as a spherical vesicle containing hydrolytic enzymes
what is the luminal pH of lysosomes?
4.5-5
how do digestive enzymes get to the lysosomes/how are lysosomes produced?
produced in the ER, transported to golgi, which produced lysosomes
what do lysosomes do? (2)
- digest macromolecules, microorganisms, and old cell fragments
- facilitates apoptosis if the cell is given the signal to die
