Cellular Functions 1 Flashcards
anatomy
study of structure and form
physiology
study of function of body
pathophysiology
study of disordered body function
ex. study of disease
What are most cells made mostly of?
water (80%) and proteins (20%)
What are the three factors of the cell theory?
cells are basic working unit of life, all living things are made of one or more cells, new cells arise from preexisting cells
cytology
study of cells
microscopy
using a microscope to view small structures
light microscope
produces a two dimensional image when light passes through specimen
transmission electron microscope
directs an electron beam through thin-cut sections to give 2-D images
scanning electron microscope
directs an electron beam across surface of specimen to give 3-D images
What are the main differences between eukaryotic and prokaryotic?
eukaryotic have nucleus, membrane bound organelles, and DNA
prokaryotes have DNA but it’s in the cytoplasm
What is the purpose of the nucleus?
controls cells
contains DNA (genetic material)
contains nucleolus
nuclear envelope
nuclear membrane of nucleus
double phospholipid
continuous with rough ER
nucleoplasm
fluid within the nucleus
What are found in the cytoplasm?
cytosol, organelles, and inclusions
cytosol
viscous fluid of cytoplasm that’s mostly made of water and some dissolved macromolecules and ions
membrane-bound organelles
have membrane which allows activities to happen in an isolated environment.
ex. ER, Golgi, mitochondria
non-membrane bound organelles
no membrane so interact with things around them
made of proteins
ex. ribosomes, centrosome, cytoskeleton
inclusions
stored temporarily in the cytosol
aggregate of a single type of molecule (not organelles)
ex. pigments, glycogen
5 main functions of cells
maintain integrity and shape, gets nutrients and forms chemical building blocks, disposes of waste, cell division for some
nuclear pores
passageways formed by proteins
nucleolus
no membrane
made of protein and RNA
makes small and large ribosome subunits
not in all cells; many if the cell makes a lot of proteins
what is DNA made of
nucleotides and 5 carbon deoxyribose and phosphate backbone
deoxyribonucleotide
DNA
made of a 5 carbon sugar deoxyribose and phosphate backbone and one of the four nitrogenous bases or “rungs” of the ladder
phosphodiester bonds
link nucleotides in DNA
histones
nuclear proteins that the double helix is wound around
provide support for the DNA strand
nucleosomes
histone and nuclear proteins
chromatin
DNA that is not dividing and in a mass
chromosomes
DNA that is dividing
gene
stretches of nucleotides that provide instructions for making of specific proteins
What are the four major steps of protein synthesis?
transcription, mRNA processing, translation, and post translational processing
transcription
occurs in nucleus
pre-mRNA molecule is made from ribonucleotides using DNA as template
done by RNA polymerase
mRNA processing
pre-mRNA is spliced (introns are removed), capped, and a polyA tail is added
it is then mature mRNA and leaves the nucleus
What happens during splicing
noncoding regions (introns) are removed
coding regions (exons) are put together to form spliceosomes
translation
occurs in ribosomes in the cytosol
mRNA thread through ribosome
mRNA is read to direct tRNAs in adding amino acids
protein molecule is formed
post translational modifications
folding and splitting of proteins after protein synthesis to make them into a functional form
pre-mRNA
large immature single stand of RNA that has exons and introns
small nuclear RNA
directs the splicing of pre-mRNA to form mRNA
messenger RNA
carries the genetic code to cytoplasm for controlling the type of protein formed
ribosomal RNA
joins with proteins to form the ribosomes where protein molecules are actually assembled
transfer RNA
transports activated amino acids to the ribosomes to be used in assembling the protein molecule
microRNA
single stranded RNA molecules of 21-23 nucleotides that can regulate gene transcription and translation
endoplasmic reticulum
interconnected membrane network that extends from nuclear envelope to plasma membrane
point of attachment for ribosomes
rough ER
makes proteins and sends them out in vesicles to Golgi apparatus for further modification
smooth ER
synthesis, transport, and storage of lipids
carbohydrate metabolism
detoxification of drugs, alcohol, and poisons
Golgi apparatus
made of elongated, flattened, membranous sac
modifies, packages, and sorts proteins that are made by the rough ER into vesicles
lysosomes
contain digestive enzymes made by the Golgi
digest unneeded substances
digests contents of endocytosed vesicles
peroxisomes
pinches off vesicles from rough ER
use proteins to serve as their enzymes
plays a role in chemical digestions, beta oxidation, and making of lipids
breaks things down
mitochondria
aerobic cellular respiration
complete digestion of fuel molecules to make ATP or energy
ribosomes
made in nucleolus and assembled in cytoplasm
bound ribosomes
attached to surface of ER
make proteins for export, become part of plasma membrane, or serve as enzymes in lysosomes
free ribosomes
suspended within the cytosol
makes all other proteins
more important than bound ribosomes
proteasomes
located in cytosol and nucleus
digest damaged and incorrectly folded proteins through ATP dependent pathway
proteins have a ubiquitin tagged so the proteasomes know which ones to digest
centrosome
pair of centrioles
organizes microtubules within cytoskeleton
functions in cell division
cytoskeleton
framework of diverse proteins that extends beneath the plasma membrane and through the interior of cell
helps with intracellular support, organization of organelles, cell division, and movement of materials
made of microfilaments, intermediate filaments, and microtubules
microfilaments
smallest
actin protein monomers
maintain cell shape, internal support, and cell division
intermediate filaments
medium sized and more rigid
structural support and cell junctions
microtubules
largest
made of tubulin
can be elongated and shortened as needed
maintain shape, cell transport, and cell division
4 functions of plasma membrane
physical barrier between cell and fluid that surrounds it, regulates movement in and out of cell, establishes and maintains electrochemical gradient, and functions in cell communication
what are the three lipids that make up the plasma membrane
phospholipids, cholesterol, and glycoproteins
phospholipid features
polar, hydrophilic head
non polar, hydrophobic tails
purpose of phospholipid bilayer
keeps cytosol inside the cell and interstitial fluid outside
cholesterol features in terms of phospholipid bilayer
lipid molecule found within the bilayer
strengthens membrane and stabilizes it against extreme temperatures
only found in animal cells
glycolipids features in terms of phospholipid bilayer
lipids with attached carb groups
located on outer phospholipid region
help to form glycocalyx
importance of glycocalyx
cell-to-cell recognition aka self vs non-self
is the plasma membrane insoluble or soluble to water
insoluble - water molecules cannot get into the cell
non-polar substances can readily penetrate
membrane proteins
things like channels that are embedded in the plasma membrane and allow things into and out of the cell
integral membrane protein
embedded into phospholipid bilayer
can be a glycoprotein
peripheral membrane protein
not embedded into phospholipid bilayer
loosely attached to inside or outside
function of transport proteins and different types
regulate movement of substances across membrane
channels
carrier proteins
pumps
symporters
antiporters
identity marker
communicate to other cells that the cells belong to body
keeps the cell from being targeted to be killed
anchoring site purpose
secures cytoskeleton to plasma membrane
cell-adhesion protein purpose
help cells stick to each other
