Chapter 3: Cells Flashcards
Cell
The most basic unit of any organism. The smallest unit of life that can function independently and perform all necessary functions of life
Cell Theory
All living things are made up of one or more cells and all cells arise from other pre existing cells
Eukaryotic Cell
Has a central control structure called a nucleus which contains the cells DNA
Prokaryotic Cell
Does not have a nucleus. It’s DNA resides in the cytoplasm
4 Basic Structural Features of Prokaryotes
Plasma Membrane, cytoplasm, ribosomes, and DNA
Plasma Membrane
Encompasses the cell.
Cytoplasm
Refers to the cells content contained within the plasma membrane. Includes jelly like fluid and the cells genome
Ribosomes
Are little granular bodies where proteins are made
DNA
Each prokaryote has one or more circular loops or linear strands of DNA
Cell Wall
Protects and gives shape to the cell
Flagellum
Many prokaryotes have this whip like projection of the plasma membrane and moves the cell through the medium it lives in
Pili
Hair like projections that help prokaryotes attach to surfaces and serve as tubes through which they exchange DNA
Nucleus
A membrane enclosed structure that contains linear strands of DNA
Organelles
Specialized structures that are enclosed separately within the cell
Phospholipid Bilayer
Hydrophilic heads extend toward the intracellular and extra cellular fluid while the hydrophobic tails are directed away from these watery fluids
Receptor Proteins
Are surface or transmembrane proteins that bind to chemicals in the cells external environment
Recognition Proteins
Are surface or transmembrane proteins that give each cell a fingerprint that makes it possible for the body’s immune system to distinguish between cells
Transport Proteins
Are transmembrane proteins that help polar or charged substances pass through the plasma membrane
Membrane Enzymes
Are surface or transmembrane proteins that accelerate chemical reactions on the membranes surface
How does Cholesterol help the plasma membrane?
Helps the membrane maintain its flexibility, preventing the membrane from becoming too fluid or floppy
Passive Transport
Molecular movement without the input of energy
Diffusion
Is passive transport where a particle moves from an area of high concentration to an area of low concentration
Simple Diffusion
Molecules pass directly through the plasma membrane without the assistance of another molecule
Facilitated Diffusion
Molecules move across the plasma membrane with the help of a channel or carrier molecule
Osmosis
Diffusion of water across a membrane
Active Transport
A transport that requires the use of energy
Tight Junctions
Form continuous water tight seals around cells. Prevent fluid flow between cells
Desmosomes
Hold cells together but are not water tight allowing fluid to pass around them
Gap Junctions
Open channels between 2 cells allowing sugars and amino acids to pass through
Nuclear Membrane
Surrounds the nucleus and separates it from other parts of the cytoplasm
Chromatin
Thin fibers consisting of DNA with some proteins attached that keep the DNA from getting tangled
Nucleolus
An area near the nucleus where ribosomes are assembled
Cytoskeleton
Provides shape and support, controls intracellular traffic flow, and enables movement
Mitochondria
All purpose energy converters that are present in nearly all plant cells, animal cells, and other eukaryotic cells
Lysosomes
Are vesicles that dispose of garbage in the cell
Rough Endoplasmic Reticulum
Primary function is to package proteins that will be shipped to other locations in the endomembrane system
Smooth Endoplasmic Reticulum
Primary function is the synthesis of lipids such as fatty acids, phospholipids, and steroids. Detoxifies molecules such as alcohol
Golgi Apparatus
Processes molecules synthesized in the cell and packages those that are destined for use elsewhere in the body
Plant Cell Wall
Provides the cell with structural strength, gives the cell increased water resistance, and provides some protection from insects
Plasmodesmata
Connects cells to each other and enabling communication and transport between them
Central Vacuole
Stores nutrients, retains waste products, accumulates poisonous materials, contains pigments, and provides physical support
Chloroplast
Site of photosynthesis. The conversion of light energy to chemical energy
Stroma
Contains some DNA and protein making machinery
Thylakoids
Light is collected for photosynthesis on the membranes
