Cells Flashcards
What are Cells?
Cells are the smallest structural and functional living unit.
How many cells does the human body have?
The human body has over 100 trillion cells.
Four common characteristics of human cells
- Plasma Membrane
- Cytoplasm
- Organelles
- Nucleus
What are the functions of cells?
- Cells perform all of the processes that sustain life.
- Each cell has a different function.
Examples of processes cells perform
- Respiration
- Movement
- Reproduction
- Digestion
Examples of cell functions:
- Immune cells
- liver cells
- muscle cells
Cell Membrane Transport
- Vital component to cell function and ability to live
- Transport nutrients into the cell
- Transports waste products out of cell
Two types of cell membrane transport
1) Passive: No energy required
2) Active Transport: Uses ATP to move solutes and/or substances across the plasma membrane
Passive Transport: Diffusion
Molecules or ions move from HIGH concentration to LOW concentration until reaching equilibrium
Two types of diffusion
1) Facilitated Diffusion: Needs a facilitated carrier like a protein channel
2) Osmosis: Through a permeable membrane; Can disrupt cell volume
Passive Transport: Osmosis
A) Isotonic Solutions
B) Hypertonic Solutions
C) Hypotonic Solutions
Passive Transport: Isotonic Solutions
Cells retain their normal size and shape in isotonic solutions (salme solute/water concentration as inside cells; water moves in and out)
Passive Transport: Hypertonic Solution
Cells lose water by osmosis and shrink in a hypertonic solution (contains a higher concentration of solutes than are present inside the cells)
Passive Transport: Hypotonic solutions
Cells take on water by osmosis until they become bloated and burst (lyse) in a hypotonic solution (contains a lower concentration of solutes than are present in cells)
Cellular Structure: Plasma membrane
- The boundary of the cell
- Controls interaction with other cells
- Controls the movement of substances in and out of the cell : Selectively Permeable
Cellular structure: Nucleus
The center of the cell
Cellular Structure: Cytoplasm
A gel-like substance surrounding the nucleus and packed with various organelles and molecules, each of which serves a specific function.
Plasma Membrane is composed of:
- Lipids
- Proteins
- Carbohydrates
Organelles of Cell
Like little machines of the cell. Each organelle has a specific structure and function
Inclusions of Cytoplasm
- Fat droplets
- Granules of glycogen
- Vacuoles and crystals
Nuclear Envelope
- Surrounds the nucleus
- Double-layered membrane
Nuclear pores
Perforates the nuclear envelope
-Regulates the passage of molecules into/Out of the nucleus (Such as those needed for construction of RNA and DNA)
Chromatin (In nucleus)
Extends throughout the nucleoplasm (substance filling the nucleus
-Thread like structures composed of DNA and protein
Chromosomes (In nucleus)
Tightly coiled Chromatin into short, rod-like structures
Cellular Organelles: Nucleolus (In nucleus)
- Center of the nucleus
- Manufactures components of ribosomes
Cellular Organelles: Ribosomes (in nucleus)
Protein-producing structures in the cell
Cellular Organelles: Mitochondria (In nucleus)
Location of ATP production
Cellular Organelles: Endoplasmic Reticulum (ER)
- Modifies proteins
- Rough ER and smooth ER
Cellular Organelles: Golgi Apparatus
Modifies and packages proteins and lipids
Cellular Organelles: Lysosomes/Peroxisomes
Contains digestive enzymes and molecules to break down waste
Cellular Organelles: Cytoskeleton
Protein microtubes and filaments to structural support cell
Cellular Extension: Cilia
- Whiplike, extensions on surfaces of some cells
- Move substances, like mucus, along
Cellular Extensions: Microvilli
- Smaller finger like projections from cell
- Increased surface areas to improve absorption
Cellular Extensions: Flagella
Whiplike, motile extensions on surfaces of certain cells
