Chapter 3 Flashcards
Three parts of a cell
Cytosol: ICF (water, dissolved solutes, suspended material)
Organelles: specific functions/shape
Nucleus: houses DNA has chromosomes (single molecule of DNA) that contain genes
Cytoplasm vs cytosol
Cytoplasm: houses everything in a cell besides membrane/nucleus
Cytosol: fluid portion of cytoplasm
Lipid Bilayer characteristics
75% phospholipids (amphiatic), cholesterol (amphiatic), glycolipids (only in layer facing ECF)
Protein arrangement in lipid bilayer (integral, trasbmembrane, glycoproteins, peripheral)
Integral: firmly embedded into/through lipid bilayer (amphiatic)
Transmembrane proteins: integral proteins protruding into Cytosol/ECF
Glycoproteins: integral proteins with carbohydrate group attached
Peripheral Proteins: not firmly embedded, attracted to polar head/integral proteins
Ion channels
Selective pores/holes for ions to travel
Carriers/transporters
Move polar substance/ion
Receptor
Cellular recognition sites, binds specific ligand
Enzyme
Catalyze chemical reactions
Linker
Anchor proteins together or to microfilaments
Cell identity marker
Recognize cells/respond
Membrane fluidity
Double bond=kink=can’t pack together tightly=fluidity
Selective permeability
Some substances pass more easily than other in lipid bilayer
More hydrophobic/lipid soluble=more permeable
Highly permeable substances
Non polar, CO2, steroids
Moderately permeable substances
Small uncharged, polar molecules
Impermeable substances
Ions, large uncharged polar
Electrochemical gradient
Electrical: inner surface plasma membrane=neg charge, outer surface=pos charge
Concentration: difference in concentration
Membrane potential
Electrical gradient across membrane
Passive transport/what makes it easier
No energy, move down gradient
Steepness of concentration gradient: higher concentration difference= faster
Temperature: higher temp=faster
Mass of diffusing substance: larger mass=slower
Surface area: larger SA=faster
Diffusion distance: greater distance=slower
Active transport def/types
Energy used, moves against gradient
Primary active
Secondary active
Receptor mediated endocytosis
Phagocytosis
Bull phase endocytosis
Exocytosis
Transcytosis
Passive transport types
Simple diffusion
Facilitated diffusion
Osmosis
Simple diffusion
Movement down fence ration gradient not using transmembrane proteins
-nonpolar, hydrophobic solutes: (O2,CO2,N gases)
fatty acids, steroids, fat soluble vitamins
-polar molecules : water, urea, small alcohols
Facilitated diffusion
Simple but uses tans-membrane proteins (carriers/channels)
-polar or charged solutes, glucose, fructose, galactose, vitamins, K+, Cl-, Na+, Ca2+
Osmosis
Movement of water molecules from high to low water concentration
-solvent: water
Primary active transport
Against concentration gradient by pumps using energy supplied by hydrolysis of ATP
Ions: Na, K, Ca, H, I, Cl (pretend they have charges)
Secondary active transport
Uses energy indirectly
Anitporters: move 2 substances in opp direction
Symporters: move 2 substances in same direction
Receptor mediated endocytosis
Ligand-receptor complexes trigger infolding of clathrin-coated pit that forms a vesicle containing ligands
-transferrin, low density lipoproteins, vitamins, hormones, antibodies
Phagocytosis
Cell eating
-bacteria, viruses, dead/aged cells
Bulk phase endocytosis
Cell drinking
-solutes in ECF
Exocytosis
Move substances out of a cell in secretory vesicles
-neurotransmitters, hormones, digestive enzymes
Transcytosis
Endocytosis on one side Exocytosis on the other
-antibodies between blood plasma and interstitial fluid
Cytoplasm structure/function
Cytosol: 55% of cell volume, mostly water
-sure if chemical reactions
Cytoskeleton: made of protein filaments, extends through Cytosol
-microfilaments
-intermediate filaments
-microtubules
Microfilaments
Thinnest
Generate movement/provide support (microvilli=increase SA)
Intermediate filaments
Stabilize position of organelles/attach cells to one another
Microtubules
Made of tubulin
Shape of cell/movement of organelles/specialized cell projections
Centrosome
Microtubules organizing center
Pair of centrioles+pericentriolar matrix
Contains tubulins for growth of mitotic spindle/microtubule formation
Cilia/flagella
Cilia: oar beating, move fluid along cells surface
Flagella: wavelike, move entire cell
Ribosomes
Site of protein synthesis
Along ER, in nucleus, along nuclear membrane
Endoplasmic Reticulum
Rough: has ribosome, folded along nuclear membrane
- produce secretory, membrane, organellar proteins
Smooth: no ribosomes, extend from rough
-synthesize fatty acids/steroid, inactivates/detoxifies drugs, removed phosphate group from glucose-6-phosphate, releases calcium ions that trigger contraction in cells
Golgi complex
Consist of 3-20 cisterns
Entry, medial, exit face
-proteins move from entry to exit by transport vesicles, leave through secretly/membrane vesicles after being modified/sorted/packaged
Lysosomes
Vesicles formed from golgi complex
Powerful digestive/hydrolytic enzymes that break molecules once lysosomes fuse with vesicle, recycle worn out cell structures
Autophagy
Digestion of organelles
Autolysis
Digestion of entire cell
Perioxomes
Contain several oxidases (enzymes that oxidize several substances)
Proteasomes
Destruction of uneeded/damaged/faulty proteins
Mitochondria
Powerhouse of the cell/generate most ATP
External and internal (mitochondrial cristae (folds), mitochondrial matrix) membrane
Structure/function of nucleus
Nuclear envelope: double membrane=lipid bolsters
Nuclear pores: openings controlling movements between cytoplasm and nucleus
Chromosomes: consists of genes confront cellular structures/functions
Genes
Hereditary unburden, arranged along chromosomes
Nucleoli
Produce ribosomes
Synthesize rRNA
Chromatin
Forms chromosomes, bead on string structure
Neculosome
Bead of chromatin
Histones: 8 form bead
Linker DNA
String of chromatin
Genome
Genetic information in a cell/organism
Protein synthesis events
Transcription
Translation
Transcription
mRNA binds to ribosomal subunit, initiator tRNA binds to start codon on mRNA, codes for methionine
Large+small ribosomal attatch=functioning ribosome, imitator tRNA with methionine go to P site
Anticodon of incoming tRNA pairs with next mRNA at A site
Amino acid on tRNA at P site form peptide bond with amino acid at A
2-peptide born moves fully to A site
Everything shifts one codon A—>P, P—>E
Continuous until stop codon UAG
Protein synthesis site letters order
E,P,A
Somatic cell division
Mitosis (interphase, mitotic phase)
Cytokinesis
Interphase
G1: cel metabolically active, duplicates organs/cystolic components, centrosome replication begins (8-10 hours)
S: DNA replicated (8 hours)
G2: growth continues, enzymes/proteins synthesized, centrosome replication completed (4-6 hours)
G0: nondividing cell
Mitotic phase
Prophase: chromatin divers condense/shorten into chromosomes, centrosome from mitotic spindle, chromatids separate, nucleus/nuclear envelope disappears
Metaphase centromere align along. Metaphase plate
Anaphase: centromeres split=seperate chromatid pairs into chromosome
Telophase: chromosomes uncoil to chromatin form, nucleolus reappears, mitotic spindle breaks
Cytokinesis
Cleave furrow, contractile ring tightens until cell splits
Starts during late anaphase
Reproduce cell division
Meiosis 1
Meiosis 2
Meiosis 1
Prophase 1:
-synopsis: two sister chromatids of each pair of homologous chromosomes pair off
-tetrads: resulting 4 chromatids form tetrad
-crossing over: exchange of genes between chromatids
-genetic recombination: formation of new gene combination
Anaphase: paired chromosomes remain together
Otherwise same as mitosis
Meiosis 2
Same as mitosis but ends with four haploid cells genetically different from starting cell, don’t copy DNA in interphase 2
Size of cells
Micrometers: 1/1000000 of a meter
8micrometers to 140 micrometers
Shape of cells
RBC: flat for SA for oxygen passing
Microvilli on epithelial cells: increase SA for digestion in GI
Nerves: long extension to conduct never impulses over great distances
Smooth muscle cell: log spindle shape contracts to allow more/Les blood flow
Crenation
Water molecules leave cell shrinking them
Hemolysis
RBC burst from too much water
Tonicity
Measure of the solutions ability to change the volume of cells by altering their water content
Isotonic solution
Cells maintain regular shape
Hypotonic solution
Lower concentration of solutes than Cytosol in cells
Hypertonic solution
Higher concentration of solutes than Cytosol in cells
Aquaporins
Integral membrane proteins acting as a water channel
Hydrostatic pressure vs osmotic pressure
Pushing force due to more fluid in one area
Pulling force due to solutes in one area
Autophagosome
Vesicle created by ER to first organelle during autophagy
Apoptosis
Orderly genetic programming of a cells death
Proteome
All of an organisms proteins
Codon
3 nucleotides ex AUG
Genetic code
Set of rules relating base triplet of DNA codon to RNA/amino acids
Somatic cell
Anything other than a germ cell
Germ cell
Gamete (sperm, oocyte)
Diploid
2 sets of chromosomes
Haploid
1 set of chromosomes
