Biology Chapter 3 Flashcards
The smallest unit of living matter that can carry out all processes required for life
Cells
Cell Theory: 3 Parts
-All organisms are made of cells
-All existing cells are produced by other, living cells
-The cell is the most basic unit of life
Discovery of Cells: Robert Hooke (1665)
Identified cells with a cork and his microscope and named them cells (like a monastery)
Discovery of Cells: Leeuwenhoek (1674)
Made better lenses; observed cells in greater detail
Discovery of Cells: Schleiden (1838)
Discovered that plants are made of cells
Discovery of Cells: Schwann (1839)
Concluded all living things are made of cells
Discovery of Cells: Virchow (1855)
All cells come from other cells
A boundary that encloses all cells and controls the movement of materials in & out of it
Cell membrane
A jellylike substance within the cell that contains dissolved molecular building blocks-proteins, nucleic acids, minerals, ions
Cytoplasm
Structures specialized to perform distinct processes within a cell; ex: nucleus
Organelles
The type of cells that do not have a nucleus or other membrane-bound organelles; the cells DNA is suspended in the cytoplasm; microscopic single-celled organisms
Prokaryotic Cells
These types of cells have a nucleus and other membrane-bound organelles; the nucleus (largest organelle) encloses the genetic information; can be multi-cellular or single-celled
Eukaryotic Cells
A network of proteins that is constantly changing to meet the needs of a cell;
Gives the cell its shape; serve as tracks for the movement of organelles
Give a cell its strength
Enable cells to move and divide
Cytoskeleton
The storehouse for most of the genetic information, or DNA in your cells; contains genes that are instructions for making proteins
Nucleus
2 Major Demands on the Nucleus
-DNA must be carefully protected
-DNA must be available for use at the proper times
Nucleus Structure:
Composed of the cell’s DNA enclosed in a double membrane called the nuclear envelope; pierced with holes called pores
Nucleus Structure:
Composed of the cell’s DNA enclosed in a double membrane called the nuclear envelope; pierced with holes called pores that allow large molecules to pass between the nucleus and cytoplasm
Contains nucleolus; produces ribosomes
An interconnected network of thin folded membranes; smooth & rough; studded with ribosomes that link amino acids together to form proteins; aids in the production of proteins and lipids
Endoplasmic Reticulum
Tiny organelles that link amino acids together to form proteins; primarily in rough ER
ribosomes
The interior of the ER
lumen
ER without ribosomes; makes lipids
Smooth ER
Help store energy and make up cell membranes and organelles
Lipids
Nucleus contains instructions to make proteins (DNA and RNA)–> gives instructions to ribosomes to link amino acids and form proteins (ribosomes are on the ER)–> proteins travels down the ER–> at the end of the ER, a part of the ER pinches off to form a vesicle which transports a protein to the Golgi Apparatus–> Golgi Apparatus makes any modifications and then packages proteins into vesicles which take them to wherever they need to go
Protein Production
Closely layered stacks of membrane-enclosed spaces that modify, process, sort, package, and deliver proteins
Golgi Apparatus
Small, membrane-bound sacs that divide some materials from the rest of the cytoplasm and transport these materials from place to place within the cell (also transport proteins)
Vesicles
Supplies energy to the cell; bean shaped and have two membranes; Chemical reactions convert molecules from the food you eat into useable energy; have their own DNA
Mitochondira
A fluid-filled sac used for the storage of materials needed by a cell
Vacuole
Membrane-bound organelles that contain enzymes; defend a cell from invading bacteria and viruses; break down damaged or worn-out cell parts (enzymes are proteins)
Lysosomes
Cylinder-shaped organelles made of short microtubules arranged in a circle; divide DNA during cell division, help form cilia and flagella
Centrioles
A small region of cytoplasm that produces microtubules
Centrosome
Two features unique to Plant Cells:
Cell walls and chloroplasts
Found in both prokaryotic and eukaryotic cells (3):
DNA
Cell Membrane
Cytoplasm
Surrounds the cell membrane in plant cells; a rigid layer that gives protection, support, and shape to the cells
Cell Wall
Organelles found in plant cells that carry out photosynthesis; convert solar energy into energy-rich molecules that the cell can use
Chloroplasts
Forms a boundary between a cell and the outside environment and controls the passage of materials into and out of a cell
Cell Membrane
Make up a cell membrane; composed of a polar head and nonpolar tails
Phospholipid
How are phospholipids arranged so accommodate for polarity
Polar heads facing the outsides
Nonpolar tails facing the insides
Which molecules are imbedded within phospholipid heads that help determine the type of cell
Carbohydrates
Describes the arrangement of the molecules that make up a cell membrane
Fluid Mosaic Model
A property of the cell membrane that allows some, but not all, materials to cross
Selective Permeability
Why is the ‘G’ in Golgi Apparatus always capitalized?
It is named after a famous scientist
A protein that detects a signal molecule and performs an action in response; only recognizes and binds to certain molecules
Receptor
The molecule a receptor binds to
Ligand
When a receptor and a ligand bind, they _____ _____
Change Shape
Receptor found within the cell
Intracellular Receptors
Receptors found within the cell membrane
Membrane Receptors
The movement of molecules across a cell membrane without energy input rom the celll
Passive Transport
The movement of molecules in a fluid or a gas from a region of higher concentration to a region of lower concentration, resulting from the natural motion of particles (causing particles to collide and scatter)
Diffusion
The number of molecules of a substance in a given volume
Concentration
The difference in the concentration of a substance form one location to another; molecules diffuse down this
Concentration Gradient
The process of water molecules diffusing, or moving across a cell membrane from an area of higher to lower water concentration
Osmosis
A solution is _____ to a cell if it has the same concentration of dissolved particles as the cell; water molecules move in and out of the cell at an equal rate, so the size remains constant
Isotonic
A _____ solution has a higher concentration of dissolved particles than a cell; more water exits the cell than is entering the cell, causing a cell to shrivel up and die
Hypertonic
A _____ solution has a lower concentration of dissolved particles than a cell; water is coming (diffusing) into the cell faster than water is exiting the cell causing a cell to expand or burst
Hypotonic
Opening formed by proteins that pierce the cell membrane; allow molecules that cannot diffuse easily to enter a cell
Transport proteins
The diffusion of molecules across a membrane through transport proteins
Facilitated Diffusion
Transport proteins that move materials against a concentration gradient
Pumps
Drives molecules across a membrane from a region of lower concentration to a region of higher concentration, thus requiring chemical energy
Active Transport
The process of taking in liquids or fairly large molecules into a cell by engulfing them in a membrane; the cell membrane makes a pocket around a substance; the pocket breaks off inside the cell and forms a vesicle which then fuses with a lysosome that breaks down the vesicle membrane to release its contents into the cell
Endocytosis
A type of endocytosis in which the cell membrane engulfs large particles; “cell eating”
Phagocytosis
The opposite of endocytosis; the release of substances out of a cell by the fusion of a vesicle with the the membrane; forms a vesicle around the material; vesicles fuses with the cell membrane and releases the contents
Exocytosis
