Cell Structure Flashcards
What are the 3 main cell structures?
- Plasma Membrane
- Cytoplasm
- Nucleus
Structure that separates intracellular from extracellular environments. Consists of lipid bilayer.
Plasma Membrane
Lipid bilayer consists of these 3 types of lipids:
Phospholipids (75%), cholesterol (20%), glycolipids (5%)
Phospholipids’ _____ is/are polar and Hydrophilic, and face outward
Head
Phospholipids’ _____ is/are nonpolar and hydrophobic, facing toward one another.
Tails
Proteins that are weakly attached to polar heads or integral proteins on the inner or outer surface
Peripheral Proteins
Proteins that are firmly embedded in the plasma membrane
Integral membrane proteins
Integral membrane proteins carry out what 4 functions within the plasma membrane?
- Transport
- Identification
- Signaling
- Connection
Gel-like substance of cells that contains tiny suspended structures
Cytoplasm
Watery solution throughout the Cytoplasm. Suspends organelles and allows chemical reactions to occur in it.
Cytosol
Specialized structures in the cell
Organelles
Membrane system that is continuous with the nuclear membrane.
Made up of canals with membranous walls and flat curving sacs arranged in parallel rows
Endoplasmic Reticulum (ER)
Broad, flattened sacs studded with ribosomes; attached to nuclear envelope
Rough E.R.
Tubular sacs containing no ribosomes further away from the nuclear envelope
Smooth E.R.
Membranous organelle consisting of flattened sacs stacked together that modify and package proteins for transport (cell’s postal service)
Golgi Apparatus
Contain enzymes that digest protein structures of defective cell parts. Breaks down proteins into amino acids for reuse.
Lysosomes
Protein-destroying organelle that is a hollow, cylindrical drum made up of protein subunits
Proteasomes
Organelle which contains enzymes that detoxify and neutralize dangerous/harmful substances through oxidation.
Cell’s own “immune system”
Peroxisomes
Powerhouses of the cell - provide most of the cell’s ATP supply
Mitochondria
ATP
- Adenosine Triphosphate
- High Energy bonds between phosphate groups
a series of chemical reactions used by all aerobic organisms to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins into carbon dioxide and chemical energy in the form of adenosine triphosphate (ATP)
Citric Acid Cycle (CAC)
(Krebs Cycle)
(Tricarboxlic Acid Cycle, TCA)
Control center of the cell located in the cell’s center.
Is large in structure enclosed by two membranes with many pores
Nucleus
Double membrane layer (lipid bilayer) with nuclear pores.
Controls movement of substances between nucleus and cytoplasm
Nuclear Envelope
Cluster of protein, DNA, and RNA within the nucleus that are the sites for ribosome production
Nucleolus/Nucleoli
Formed from DNA, proteins, and some RNA; Takes the form of chromosomes in dividing cells
Chromatin
Network of protein filaments extending throughout the cytosol that contribute to the structure of the cell and organelles
Cytoskeleton
protein filament composed of actin and myosin (proteins), prevalent at the edge of the cell, generate movement and provide mechanical support
Microfilaments
Protein filament that is very strong, found in parts of cells subject to mechanical stress
Intermediate filaments
protein filament that helps determine shape, function in the movement or organelles, and specialized projections
Microtubules
Located near nucleus, coordinates building and breaking apart of microtubules. Play role in cell division
Centrosome
Barrel-shaped organelles comprised of microtubules. Form bases for cilia and flagella
Centrioles
projections that extend the plasma membrane outward to form fingerlike processes
Cell extensions
What are the 3 types of cell extensions?
- Microvilli
- Cilia
- Flagella
small finger-like extensions of the plasma membrane that increase surface area of the cell for absorption
Microvilli
tiny “whip-like” projections of the cell surface that contain microtubules. They propel substances across the cell-surface
Cilia
Similar to cilia in structure, propel the entire cell
Found in sperm cells
Flagella
Steroid lipid that mixes in with the phospholipids to make the bilayer fluid enough to function at body temperature
Cholesterol
Plasma membrane is Amphipathic which means:
Lipids in the bilayer have both polar and nonpolar parts
Most of the phospholipid bilayer is ________.
hydrophobic. (water or water soluble molecules do not pass through easily)
______ molecules pass through the plasma membrane easily
Lipid-soluble
Rough ER synthesizes _______ and _______
glycoproteins and phospholipids
Smooth ER synthesizes ______ and _______
fatty acids and steroids
a non-membranous organelle attached to ER or floating in cytoplasm that is the site of protein synthesis
Ribosomes
Ribosomes are comprised of these 2 subunits:
ribosomal RNA, and proteins
Membrane enclosed vesicles that form from the Golgi Complex
Lysosomes
Organelle that breaks down abnormal and misfolded proteins released from the ER and destroys normal regulatory proteins in cytoplasm that are no longer needed.
DESTROYER OF PROTEINS!
Proteasomes
Production and breakdown f hydrogen peroxide occurs within the _________ protecting the rest of the cell from the toxins
peroxisomes
The wall in the _______ consists of two delicate membranes - forming a sac within a sac.
The inner membrane is contorted into many folds (cristae), creating larger surface area
Mitochondria
The __________’s inner membrane contains enzymes that help to form ATP through aerobic cellular respiration
Mitochondria
The number of _______ in a cell is directly proportionate to that cell’s ability to generate energy
Mitochondria
Centrosomes are made up of these 2 components
- A pair of centrioles
- Pericentroliar material
Ring shaped complexes composed of the protein tubulin
Pericentriolar material
Cell connection that holds adjacent cells together
Found in skin cells
Desmosomes
Cell connection that forms tunnels that join the cytoplasm of 2 cells and fuse the 2 plasma membranes into a single structure
Gap Junctions
__________ allows for easy passage of certain molecules
Gap Junctions
cell connection created by fusion of similar integral membrane proteins (limit permeability)
Tight Junctions
