Chap 3 Flashcards
Cell Cycle
where cells divide, and specialize
3 Phases of Cell Cycle
- Mitosis phase
- g1/ g2 phases
- S phase
Mitosis
- cell dives into 2 daughter cells
- division of somatic cells
g1 and g2 phase
cell growth and prep for mitosis
S phases
DNA replicated
Plasma Membrane Bilayer composed of:
- phospholipids
- cholesterol
- proteins
- glycoproteins & glycolipids
Lipid bilayer maintain an internal environment, that is separate from exterior of the cell =
selective permeability
Proteins can serve as:
- anchors
- receptors
- channels
- enzymes
Types of Membrane Proteins
- Ion channel
- Carrier
- Receptor
- Enzyme
- Linker
- Cell identity
Ion Channel protein
Allows specific ions to move through water-filled pore
Carrier protein
transports substances across membrane by changing shape
Receptor protein
alters cell function
Enzyme protein
catalyzes reaction inside or outside cell
Linker proteins
Anchors filaments providing structural stability and shape for cell
4 modes of transport through membrane
Diffusion, Filtration, Carrier-mediated transport, vesicular transport
- Diffusion (passive = no ATP required)
- movement of ions across mebrane
- lipid-soluble
Osmosis (passive)
-movement of water across membrane
- Filtration (passive)
hydrostatic pressure forces water/ small molecules across membrane
- Carrier-mediated transport (passive)
a) facilitated diffusion
b) primary active transport
c) secondary active transport
a) facilitated diffusion (passive)
- movement of molecules down concentration gradient
- requires transporter for movement across plasma membrane
- transport rate = # of transporters
b) primary active transport (active)
- movement of molecules across membrane
- low to high concentation
c) secondary active trasport (active)
- Na+/ K+ pump used to trasfer molecules
- ATP used secondary
- Vesicle Trasport
- Endocytosis:
- Phagocytosis
- Pinocytosis
- Exocytosis
Endocytosis
process of transporting subtances across plasma membrance via vesicle
Phagocytosis
“cell eating” (type of endocytosis)
Pinocytosis
“cell drinking” (type of endocytosis)
Exocytosis
subtance exported out of cell via vesicle
Cytoplasm consits of:
- cytosol
- organelles
- inclusions
Cytoskeleton consists of:
- microfilaments
- microtubules
Microvilli
increases cells surface are by:
- abosorption of nutrients
- collecting sound waves
- taste/ smell receptors
Cilia
- Movement
- made of microtubules
Endoplasmic Reticulum
- synthesis: proteins, carbs, lipids
- storage
- transport
- detox
Golgi Body/ Apparatus
processes/ packages proteins and lipids
Lysosomes
digest
Secretory vesicles
horomones and proteins for export
Membrane renewal vesicles
lipids and proteins for membrane repair
Ribosomes
synthesize and release new proteins
Rough ER
- modifies/ folds proteins
- manufactures phopholipids
Smooth ER
sythesizes lipids
Nucleus - largest organelle - CONTAINS
- DNA
- Nuclear envelope
- Nuclear lamina -> supports shape
- nuclear poles -> allows diffusion of small molecules
- nucleolus -> ribosome synthesis
DNA replication occurs in what phase
S phase
DNA polymerase joins ____ together in the 5’ and 3’ direction
nucleotides
Nuclues Primary Function
store and express our genetic info.
Transcription
DNA is transcribed into mRNA
Translation
mRNA translated into protein
3 phases of translation
- Initation
- Elongation
- Termination
Initation
ribsome assembles around mRNA and 1st tRNA attaches
Elongation
- 2nd tRNA binds to next codon
- 1st tRNA transfers an amino acid to the amino acid on 2nd tRNA
Termination
when a stop codon is reached, ribosome releases polypeptide
Proteins
- basic structural material of body
- made up of amino acids
Amino Acids
linked ‘head-to-tail’ by peptide bond = polypeptides + proteins
Protein Synthesis
DNA —transcription–> RNA —-translation—>Protein
20 amino acids =
complete protein
Nitrogen balance
- nitrogen enters body via amino acids
- leaves body via urea in urine
Synthesizing greater amounts of protein =
positive nitrogen balance
Breaking down greater amounts of protein =
negative nitrogen balance
