Biology Cell Theory and Organelles Exam Flashcards
What is Cell Theory?
- All living things made of cells
- Cells are the basic unit of life
- All cells come from other cells
Organisms may be:
- Unicellular (composed of one cell)
- Multicellular (composed of many cells that may be organized into:
Tissues 🡪 Organs 🡪 Organ Systems
The two main types of cells are:
Prokaryotic and Eukaryotic
All Cells have:
- Genetic Material (DNA or RNA)
- Cytoplasm
- Cell Membrane
- Ribosomes
Organelles
- Organelles: Specialized structures within the cell that work together to help the cell function
- All cells have these four structures, but eukaryotic cells also have membrane-bound organelles.
- (Think of them as “mini organs” within the cell working together for one main purpose 🡪 TO MAKE PROTEINS!)
Cell (Plasma) Membrane
Structure:
- Surrounds the outside of ALL cells!
- Made of two layers (known as the Phospholipid Bilayer)
Job:
- Controls what goes in and out of the cell
Phospholipid Bilayer
- 2 layers of fats
- Fats = phospholipids
- Have hydrophilic (likes water) heads and hydrophobic (dislikes water) tails
- Proteins embedded for transport
Carbs embedded for structure
It is called “Fluid Mosaic Model” because it is composed of many parts that move around freely
Cytoskeleton
Structure:
- Threadlike fibers
- Made of proteins
- Usually not pictured in a cell diagram
Job:
- Give the cell shape
- Can also move organelles around
- Provide structural support for animal cells (who don’t have a cell wall)
Cytoplasm
Structure:
- Jelly-like substance
- Mainly made up of water
Job:
- Holds everything in place
- Where some chemical reactions take place
Nucleus
Structure:
- Contains genetic material (DNA)
- Surrounded by a nuclear envelope/membrane with pores that control what goes in and out
Job:
- Protects the DNA that controls the activities of the cell
Nucleolus
Structure:
- Inside of the nucleus
Job:
- Makes rRNA which make up ribosomes
Ribosomes
Structure:
- Made of proteins and rRNA
- Located on Rough ER and floating in cytoplasm
Job:
- Make (synthesize) proteins!!!
Rough ER
Structure:
- Has ribosomes on surface
- Hugs the nucleus
Job:
- Makes proteins!!!
- Packages them for secretion
Smooth ER
Structure:
- No ribosomes on surface
- Attached to Rough ER
Job:
- Makes lipids (membrane)
Golgi Apparatus
Structure:
- Folded membrane
Job:
- Gets vesicles of protein from the ER
- Vesicles: like mini-carts that transport proteins around the cell
- Processes, sorts, and ships proteins where needed
Lysosomes
Structure:
- ANIMAL CELLS ONLY!!
- Contain digestive enzymes
Job:
- Break down dead stuff (food, bacteria, old parts of cells, etc.)
- Can do programmed cell death (apoptosis)
Vacuoles
Structure:
- Small and numerous in animal cells
- One large central one in plant cells
Job:
- Storage (water, nutrients, waste, etc.)
Centrioles
Structure:
- ANIMAL CELLS ONLY!!
- Made of microtubules
- 2 centrioles together = Centrosome
Job:
- Appear during cell division
- Help cells divide by pulling chromosomes apart
Cilia
Structure:
- ANIMAL AND BACTERIA CELLS ONLY!!
- shorter, more numerous, like tiny oars
Job:
- Move fluid across cell’s surface
Flagella
Structure:
- ANIMAL AND BACTERIA CELLS ONLY!!
- Longer, fewer oars
Job:
- Move the entire cell through extracellular fluid
Mitochondria
Structure:
- Two parts: inner membrane and matrix (fluid part)
Job:
- Where cellular respiration happens
- C6H12O6 + 6O2 🡪 6CO2 + 6H2O + energy (ATP)
- (Glucose + Oxygen + Carbon Dioxide + Water + Energy)
- Breaks down chemical energy in food (glucose) to release usable energy in the form of ATP
Chloroplast
Structure:
- Two parts: grana (stacks) and stroma (fluid)
Job:
- Where photosynthesis happens
- 6CO2 + 6H2O 🡪 C6H12O6 + 6O2
- (Carbon Dioxide + Water + Gluclose + Oxygen)
- Converts light energy from sun 🡪 chemical energy in sugar
Cell Wall
Structure:
- PLANT CELLS ONLY!!
- 1st layer of the Plant Cell
- Made of cellulose (in plants), chitin (in fungi), and peptidoglycan (in bacteria)
Job:
- Protect and maintain shape
Central Vacuole
Structure:
- PLANT CELLS ONLY!!
- 1 massive central structure
- Animal cells: Small Vacuoles
- Plant Cells: Large Vacuoles
Job :
- Storage center
