Cell Biology (M1) Flashcards
What is cell biology (cytology)
Study of cellular structure
What is cell physiology
study of cellular function
Cell destiny
remain alive and functioning, grow and divide, or die
What does homeostasis need to maintain a balance between
cell multiplication and cell death
What is apoptosis
programmed cell death
what is necrosis
cell death caused by injury or infection
properties of nonmembranous organelles
lack membranes and in direct contact with the cytoplasm
what is the biggest nonmembranous organelle
ribosome
properties of membranous organelles
surrounded by one/two lipid bilayer membranes
difference between scanning electron microscopy (SEM) and transmission electron microscopy (TEM)
SEM: 3D view and can see external structures
TEM: internal structures
What units do we use for cell measurement
millimeters, microns, and millimeters
Maximum resolution of a light microscope?
0.2 microns; can’t see anything smaller than a lysosome
What is the largest organelle within a cell and its size
nucleus; 5 - 7 microns
what is a nucleus surrounded by
nuclear envelope that is composed of 2 membranes
what does the nuclear envelope contain
nuclear pores (transmembrane proteins) that messenger molecules use to pass between the nucleus and cytoplasm
are there membrane-bound organelles in the nucleus
no, only chromatin (coiled strands of DNA that condense to form chromosomes at the time of cell division)
what is the function of the nucleus
stores and transmits genetic information in the form of DNA
what are the structural characteristics of a nucleolus and what does it consist of
densely stained filamentous structure within the nucleus.
consists of proteins associated with DNA where info about ribosomal proteins is being expressed
what is the function of the nucleolus
site of ribosomal RNA (rRNA) synthesis.
assembles RNA and protein components of ribosomal subunits, which move to the cytoplasm through nuclear pores
what are ribosomes
packages of ribosomal RNA (rRNA) and protein
what type of substances pass through nuclear pores easily
very small substances
what is the function of free ribosomes throughout cytosol
synthesize proteins found inside the cell from mature mRNA
how many nuclear pores does a typical nucleus have
800 - 1000 pores
what is the structure of the er
network of membranes forming flattened sacs or tubules called cisterns
what is the attachment and function of membrane-bound ribosomes
attached to rough ER or nuclear membrane.
synthesize proteins needed for plasma membrane or export
how many membrane-bound ribosomes form a polyribosome
10 - 20
what is the function of ribosomes within the mitochondria
synthesize mitochondrial proteins
are charged amino acids hydrophobic or hydrophilic
very hydrophilic
what amino acids can cross a membrane very easily
small, uncharged nonpolar.
ex. steroid hormones
what are the types of protein structure
primary
- amino acid sequence
secondary (spiral)
- alpha helix
- beta sheet
tertiary
- bending back and globular 3D
quaternary
- multiple proteins connect by disulfide bridges and H+ bonds
difference between polar and nonpolar amino acids
polar amino acids easily interact with other polar molecules in a hydrophilic environment and nonpolar amino acids easily interact with other nonpolar molecules in a hydrophobic environment
what are the properties and functions of rough er
continuous with nuclear envelope and covered w attached ribosomes.
synthesizes, processes & packages proteins for export.
free ribosomes synthesize proteins for local use.
what are the properties and functions of smooth er
no attached ribosomes.
synthesizes phospholipids, steroids, fats, and carbs.
detoxifies harmful substances in cytosol, ex. alcohol
what is the structure of the golgi apparatus
series of cup-shaped, closely apposed, flattened, membranous sacs.
located in central portion near nucleus
what are the functions of golgi apparatus
concentrates, modifies, and sorts proteins arriving from rough er prior to distribution via golgi vesicles to other organelles or outside cell
process of protein packaging in golgi complex
- proteins pass from rough er to cis surface of golgi complex in transport vesicles
- fuse with entry cistern
- pass from entry cistern to medial cistern for processing
- transfer vesicles transport to exit cistern
- finished proteins exit golgi as secretory, membrane, or storage vesicle
where are lysosomes found
formed in golgi complex and filled with digestive enzymes
what pH do lysosomes pump in H+ ions until
5.0
what are the functions of lysosomes
digest foreign substances, ex. bacteria.
digest and recycle components of cell’s organelles (autophagy) or in cases of cell destruction (autolysis)
how are peroxisomes formed and what do they contain
formed by division of preexisting peroxisomes and contain enzymes that oxidize organic material
what are the functions of peroxisomes
normal metabolic breakdown of amino acids and fatty acids.
oxidize toxic substances like alcohol and formaldehyde
contains catalase - decompose H2O2
what chemical reaction occurs in the cytosol
production of ATP
what are the functions of cytoskeleton
provides cell support and shape.
organization of chemical reactions.
cell and organelle movement.
what are the 3 cytoskeletal filaments
microfilaments
intermediate filaments
microtubules
microfilaments
thinnest filaments (actin)
locomotion and division
support microvilli
intermediate filaments
several different proteins
anchor organelles
microtubules
large cylindrical structures composed of tubulin.
flagella, cilia, and centrosomes
what is the pericentriolar area
formation site for rapid assembly of mitotic spindle and microtubules organizing center
arrangement of centrosomes
2 centrioles 90 degrees to each other.
9 clusters of 3 microtubules (9+0 array).
vital role in formation of cilia and flagella “basal bodies”
movement of cilia
stiff during power stroke but flexible during recovery.
many coordinated together.
locations: airways and uterine tube
movement of flagella
single flagella wiggles in a wavelike pattern.
propels sperm forward
