Chapter 3/Cellular Structure, Proteins, and Metabolic Pathways Flashcards
Selective barrier: regulates passage in and out of cell and between organelles and cytosol
Membranes
-Detect chemical messengers
-Link cells together
-Anchor cell to extracellular matrix
Membranes
-Non polar fatty acids chains in the middle
-Polar regions oriented towards the surfaces of the membrane
Phospholipids bilayers
-Found in the plasma membrane
-Maintains fluidity
Cholesterol
-Amphipathic
-Associate with fatty acids in membrane
-Can span the entire membrane: transmembrane proteins
Integral membrane proteins
-Do not associate with fatty acids
-Located at the membrane surface bound to integral membrane
Peripheral membrane
-Transmembrane proteins
-Bind to specific proteins in the extracellular matrix
-Link to membrane proteins in adjacent cells
-Cells are joined physically
Integrins(membrane)
-Plasma membranes of cells are separated by about 20 nm
Desmosomes
‘Dense plaques’’ serve as anchoring points for cadherins
Desmosomes
-Cadherins extend into extracellular space and link up with cadherins of an adjacent cell
Desmosomes
-Leaves no space between adjacent cells
Tight Junction
-Occur in a band around the entire circumference of cell
Tight Junction
Form barrier that prevent movement of material through tissue
Tight Junction
-Protein channels that link the cytosols of adjacent cells
Gap junction
-Connexins from both cells join and form a protein-linked channel
Gap junction
-Small diameter (1.5 nm) limits what can pass
Gap Junction
Storage and transmission of genetic information
Nucleus
-Information coded in DNA molecules
-DNA also used to synthesize proteins
Nucleus
DNA is found in association with proteins called histones
DNA + Protein=Chromatin
-During cell division chromatin becomes condensed, forms chromosomes
Nucleus
Nuclear envelopes surrounds nucleus
-Two membranes
-Join together, form nuclear pores
-Associated with regions of DNA that contains for forms RNA found in ribosomes
Nucleolus
-Ribosomes are assembled then transferred to cytoplasm
Nucleolus
-Proteins factories
- Composed of protein and RNA
-Can be found attached to endoplasmic reticulum or floating free in the cytoplasm
Ribosomes
-Has ribosomes bound to its surface
-Packages proteins that are produced by ribosomes, sends them to Golgi apparatus
Rough ER
-No ribosomes
-Lipids are synthesized
-Detoxifies the cell
-Stores calcium
-Smooth ER
-Receives proteins from Rough ER
Golgi Apparatus
-Modifies proteins and sorts them into transports vesicles
Golgi Apparatus
- Distributes packages proteins to their intended destination
Golgi Apparatus
-Participate in cellular respiration, the process that transfer energy from nutrients to ATP molecules
Mitochondria
-Surrounded by outer membrane and inner membrane(inner membrane is folded into cristae)
Mitochondria
-Inner compartment is the matrix
Mitochondria
-Vesicles that contain acidic fluid and digestive enzymes
Lysosomes
-Break down bacteria and cellular debris that is engulfed by the cell
(also old, damaged organelles)
Lysosomes
-consumes oxygen and removes hydrogen from organic molecules
Peroxisomes
Catabolism of lipids into 2 carbon fragments that are used for making ATP
Peroxisomes
Produce hydrogen peroxide ( H2O2)
Peroxisomes
-Filament network that maintain and change the cell’s shape, produce cell movement
Cytoskeleton
Composed of G-actin
Cytoskeleton(microfilament)
Make up a majority of cytoskeleton and play important roles
Cytoskeleton (microfilament)
Cell movement, determining cell shape, cell division, and muscle cell contraction
Cytoskeleton (microfilaments)
-Composed of tubulin
Cytoskeleton (microtubules)
Microtubules and actin filament are involved with the movement of organelles
-Act as fibrous track, contractile proteins ‘‘walk’’ on them
Radiate from the centrosomes
(regulates the formation of microtubules)
cytoskeleton (microtubules)
-Hair-like, motile extension on surface of some epithelial cells
Cilia
Central core of microtubules with contractile proteins
cilia
DNA direct synthesis of proteins
Genetic Code
Sequence of DNA containing information that specifies the amino acid
sequence of a polypeptide chain
Gene
4 bases can be arranged into 64 different three
letter combinations (64 codons)
Triplet Code
An amino acid can be specified by more than one
codon
Triplet Code
any molecule or ion that is bound to a
protein
– Do not involve covalent bonding
Ligand (protein binding)
region of the protein to which
the ligand binds
Binding site (protein binding)
– Protein’s function activated or inhibited
Conformation change
the ability of a protein’s
binding site to bind specific ligands
Chemical specificity
– Binding site determines the ligand that is bound.
– Proteins must have right shape in order to bind.
* Some sites only bind one ligand, others can
bind many ligands
Protein Binding: Specificity
the strength of a ligand-protein
binding
– Determines how likely a ligand will leave the
binding site
-Same ligand may bind different proteins with
different affinities.
Affinity
Protein catalysts
-Lower the activation energy, make biological
reactions proceed at a higher rate.
Enzymes
Glycolytic pathway occurs in the
cytoplasm
_ glucose is broken down to _ pyruvate molecules
(6 carbon to 3 carbon)
1 & 2
_ ATP used, _ ATP produces
( 2 ATP total yield)
2 & 4
Series of chemical
reactions
* Oxidation of Acetyl
CoA
* More NAD+ is reduced
to NADH
– FADH2
* CO2 is produced as
waste product
Krebs Cycle
Electrons are passed (Electron
transport chain)
cytochrome
proteins
Energy released
is used to form
ATP
Electrons form
water molecules (O2 must be
present)
