Unit 2 Flashcards
Prokaryotic Cells
Simple cell, does not have a membrane bound nucleus, Bacteria + Archaea
Eukaryotic Cells
Complex cell, Membrane bound nucleus, complex, phospholipid bi-layer
Endosymbiosis Theory
Possible explanation of the origin of eukaryotic cells, cell engulfing/not digesting mitochondria and chloroplast
Nucleus
Contains DNA, chromosomes
Nucleolus
Makes ribosomes
Ribosomes
site of protein synthesis
Mitochondria
Uses glucose to create cellular energy in the form of ATP (cellular respiration), has DNA
Peroxisomes
contain enzyme catalase, breaks down hydrogen peroxide (H2O2)
Lysosomes
Break down substances inside a cell (Hydrolysis/digestion). Filled with enzymes.
Vacuoles
Used for storage, found in plants and animals (Holds water, oil, pigments for flowers, toxins)
Centrosomes
moves chromosomes during cell division, build cytoskeleton, only animal cells
Chloroplast
Plant cells only, site of photosynthesis, has DNA, produces sugar for the organism
Cell wall
Only plant cells, structure, made of cellulose
Sodium Potassium Pump
Helps to maintain osmotic equilibrium and membrane potential in cells (pumps out 3 sodium for every 2 potassium taken in)
Denaturing
The protein loses its structure and its functions.
Hydrolysis
Polymers are broken apart(digested), water is added
Gap junction
animal cells only and are gated channels
Plasmodesmata
cytoplasm exchange between plant cells
Dehydration synthesis
Monomers are bonded together to form a polymer, water is removed
main components of a cell membrane
Hydrophobic heads and hydrophilic tails, phospholipids+cholesterol, carbohydrates, proteins
aquaporin
Transport water across the cell membrane while preventing ions to pass through (sodium,potassium)
Why are cells small?
They need to be able to get in nutrients and remove waste quickly (less surface area to travel)
Hypertonic Solution
Water moves out of the cell, cell shrinks, salty outside(water moves to hypertonic solutions)
Hypotonic Solution
Water moves into the cell, cell could burst
Isotonic Solution
No net movement (equilibrium)
Osmosis
Diffusion of water (attracted to salt)
Channel Proteins
Form small openings for molecules to diffuse through (always open)
Carrier Proteins
binding site on protein surface “grabs” certain molecules and pulls them into the cell (change shape as they move along the cell membrane)
Gated channels
Similar to channel proteins, not always open
Cholesterol (lipid)
stiffens membrane by connecting phospholipids
Glycolipids (carb)
signal molecules; communicate with other cells
Glycoproteins (carb)
Have a chain of sugars; defense against foreign substances (antibodies)
Passive transport
No energy required, High to low concentration, only certain substances can pass through the membrane on their own (Diffusion)
Facilitated transport
Diffusion that is assisted by channel or carrier proteins
Contractile Vacoules
are found in fresh water organisms, pump out excess waterr
Turgor pressure
occurs in plant cells as their central vacuoles fill with water
Flaccid
plant cell draws away from the cell wall and appears limp
Active transport
moving molecules against the concentration gradient, requires energy (ATP), low to high concentration
Sodium Function
maintain nerve impulses around the body
Potassium Function
used for maintaining cell fluids and electrolyte functions
Endocytosis
taking substances into the cell, cell membrane changes shape and engulfs particles (enclosed in a vacuole)
Receptor-Mediated Endocytosis
form of endocytosis that uses proteins to alter the shape of the membrane
Exocytosis
pushing substances out of the cell, such as the removal of waste, vesicle fuses with the cell membrane and the contained material is released into the extracellular fluid
Selective Permeability
its ability to differentiate between different types of molecules, only allowing some molecules through while blocking others while passing through cell membrane
Cell surface carbohydrates are used for…
serve as points of attachment for other cells, viruses, toxins, hormones, and many other molecules
