Chapter 3 - Cells Flashcards
Eukaryotic cells
- Cells with nuclei
* In all plants and animals
Prokaryotic cells
- Cells without nuclei
* Single-cell organisms: bacteria
Protoplasm
- All the living components of a cell inside the cell wall.
* In plants and animals
Plasma membrane
- Surrounds the protoplasm, just inside the cell wall. Is the “pool liner” of the cell.
- Composed of phospholipids and embedded proteins
- Double-layer of hydrophilic/hydrophobic lipids (with tails inward) that seal the cell
- Function: regulates the movement of materials in and out of the cell (water comes and goes freely); proteins are the transport modes through the cell (materials go through the proteins like a tunnel or a ferry)
- In plants and animals
Cytosol
The fluid in the cytoplasm that organelles exist in and move through
Cell wall
- Made of cellulose
- Primary wall is thin, secondary is thick
- Function: structure
- For plants only
- Provide humans with clothing, shelter, furniture, paper, and fuel
Cellulose
The main structural component of cell walls. Composed of 100 to 15000 glucose monomers in long chains. The most abundant polymer on earth.
Hemicellulose
“Glue” that holds the cellulose fibrils together.
Middle lamella
Membrane between cells, shared by adjacent cells.
Plasmodesma/Plasmodesmata
Tiny strands of cytoplasm that extend between cells through minute openings to facilitate transport of sugars, amino acids, ions, etc. between cells.
Metabolites
Products of chemical synthesis or breakdown
Chromatin
Strands of protiens and DNA within the nucleus. During cell division, forms into coils and condenses into chromosomes.
Endoplasmic reticulum (ER)
- Membrane-consisting organelles in the cell, joined to the nucleus.
- Function: facilitates cellular communication and channeling of materials; used as a “workbench” by ribosomes to assemble amino acids for proteins, such as enzymes used in cellular respiration, and membrane synthesis
- In plants and animals
Organelles
Persistent structures of various shapes with specialized functions in eukaryotic cells; most but not all are bounded by membranes
Ribosomes
- The “supervisors” organelle of the cells
- Function: to get the jobs done as ordered by the nucleus; builds proteins (enzymes) on the ER
- Consists of RNA and proteins
- Created within the nucleus
- In plants and animals
Plastids
- A group of organelles, 3 of which are: chromoplasts, leucoplasts, chloroplasts.
- In plants only
Chromosomes
Coiled proteins and DNA formed in the nucleus during cell division.
Chloroplasts
- Organelle (a type of plastid) that contains chlorophyll pigments (green). The existence of all human and other animal life depends on the activities of chloroplasts.
- Function: photosynthesis
- In plants only
Chlorophyll
The green pigment in chloroplasts.
Chromoplasts
- Organelle, a type of plastid
- Function: contains/synthesizes and accumulates pigments, mostly carotenoid (yellow, orange, some red).
- In plants only (carrots, peppers)
Cytoplasm
Everything between the plasma membrane and nucleus: organelles and cytosol
Mitochondrion/mitochondria
- The “power station” of the cell; the energy organelle.
- Function: provides energy to the cell via cellular respiration; converts sugars to a usable form:
sugar + O2 –> ATP + CO2 + H2O
reverse of photosynthesis: aerobic cellular respiration (uses O2) - In plants and animals
Vacuoles
- Organelle
- Takes up as much as 90% of the volume in a cell
- A cell within a cell, membrane-bound
- Function: water storage for the cell; “junkyard” to store misc “stuff”; maintains turgor pressure
Cell sap
The liquid contents of the vacuole. Contains water and dissolved salts, sugars, organic acids, and soluble proteins.
Cell Theory
All living organisms are composed of cells (more than one cell, except bacteria)
Vacuolar membranes/tonoplasts
Bind one or two vacuoles in the cell
Turgor pressure
- Makes a cell rigid/full or limp. When full, results in full leaves and crisp fruit.
- At its peak in the morning
- With water loss, pressure is reduced resulting in wilting
Endosymbotic Theory
many organelles (like chloroplasts and mitochondria) were other organisms originally (bacteria) then became part of the cell
Leucoplasts
- Organelle, a type of plastid
- Clear, in seeds and roots
- Function: converts sugars to starch, synthesizes oils; stores starches and oils
Cytoskeleton
- Constructed of fibers
- Function: controls addition of cellulose to the cell wall; involved in cytoplasmic streaming; controls movement of vesicles
ATP (Adenosine Triphosphate)
has 3 phosphates; very usable energy form, easier to use than sugar as energy form (think of using coal as an energy source, vs. converting it to electricity)
