Chapter 3 Cells Flashcards
the smallest unit of life that can function independently.
The cell
used to view the entire cell
Light microscopes
used to view the parts of cells, and viruses, which are smaller and require higher magnification
Electron microscopes
transmits electrons right through cells.
transmission electron microscope (TEM)
It bounces electrons off the surface of cells.
scanning electron microscope (SEM)
have more surface area relative to their volume. High surface area allows the cell to quickly exchange materials with its surroundings.
Smaller cells
small, simple in structure and lack a nucleus.
Bacteria and archaea are two different domains
Prokaryotes
larger and more complex, with many internal parts including a nucleus and other membranous organelles.
Protists, fungi, plants, and animals.
Eukaryotes
anatomy of a bacterial cell (3 characteristics)
prokaryotic.
They lack membrane-bounded organelles.
Their ribosomes and DNA are free in the cytoplasm.
anatomy of an animal cell (2 characteristics)
eukaryotic.
They have many different membrane-bounded organelles.
anatomy of a plant cell (2 characteristics)
eukaryotic.
They have most of the same membrane-bounded organelles as animal cells, but also include the large central vacuole, cell wall, and chloroplasts.
Cell membrane (2 characteristics)
Regulates passage of substances in and out of the cell; helps maintain homeostasis.
Phospholipid bilayer. Semipermeable
Cell membranes are composed of many
Phospholipids. Form a phospholipid bilayer, which is selectively permeable to lipids and small, nonpolar molecules.
A phospholipid is made of: a molecule of glycerol, a phosphate group, and 2 fatty acids.
Cell membranes contain proteins (4). Different membrane proteins carry out different functions.
Transport proteins
Enzymes
Recognition proteins
Adhesion proteins
Receptor proteins
protrude outward from the cell membrane
Carbohydrates
Carbohydrates (Cell membrane)
Chains of sugars are attached to some of the protein and phospholipids in cell membranes.
They play roles in cell-cell communication.
The combination of phospholipids and proteins forms a
fluid mosaic.
controls protein production
The nucleus
synthesizes ribosomes.
nucleolus
synthesized in the nucleus
RNA
Proteins are synthesized on
ribosomes. Free floating ribosomes synthesize proteins that will function in the cytosol.
endomembrane system consists of (6)
nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and cell membrane.
The different parts of the endomembrane system work together to secrete_________, moving them outside the cell.
proteins
The proteins exit the rER in bubbles of membrane called transport ________.
vesicles
Secreted proteins move from _________ into the _________, where they are modified and folded into their exact 3D shape.
ribosomes, rough ER
The vesicles leaving the rER fuse with the ___________—a stack of membrane sacs that acts as a “processing center.”
Golgi apparatus
Proteins leave the Golgi in _____________.
The transport vesicles then fuse with the __________.
The contents of the vesicle are expelled to the ______________________.
transport vesicles
cell membrane
outside of the cell.
Some transport vesicles leaving the Golgi carry enzymes that catalyze hydrolysis reactions. These vesicles fuse with ____________, where cellular digestion of large molecules occurs.
lysosomes
Most plant cells lack _________.
lysosomes
Cellular digestion occurs in large central ____________, which also help regulate the size and water balance of plant cells.
vacuoles
_____________ break down toxic substances. Also aid in digestion. They originate at the ER and contain enzymes that digest and then oxidize certain toxic molecules.
Peroxisomes
Almost all eukaryotic cells have ___________, which extract energy from food.
Cellular respiration converts sugar’s energy into a form the cell can use for work.
mitochondria
The space inside the mitochondria is called _________.
the matrix
Folds in the inner mitochodrial membrane are called __________.
cristae
organelles that convert energy from sunlight into sugar, which is food for the cell.
These are the sites for the chemical reactions of photosynthesis.
chloroplasts
The space inside the chloroplast is called the ___________.
stroma
Flattened sacs of internal membranes are called ______________.
thylakoids
The sugar then travels to the_____________, which extract the energy used for cellular processes.
mitochondria
How many of these organelles occur in your skin cells?
mitochondria, ribosomes, nucleus, lysosomes, chloroplasts, vacuole, ER
five
mitochondria, ribosomes, nucleus, lysosomes, ER
The _____________ is a network of protein tracks and tubules found in eukaryotic cells.
cytoskeleton
Structural support
Aids in cell division
Organelle transport
Cell movement
Functions of cytoskeleton
The cytoskeleton has three major components
Microfilaments are composed of actin proteins.
Intermediate filaments have varied protein composition.
Microtubules are composed of tubulin proteins.
__________are needed for cell contraction and changes in cell shape.
Microfilaments
___________ ___________ form a strong scaffold for mechanical strength.
Intermediate filaments
___________ act as “trackways” for moving organelles and vesicles.
Microtubules
_____________ make up structures called _________ and __________ that protrude out from cells.
Microtubules. cilia and flagella
Airway cells need ________ to push particles like dust out of the respiratory tract.
cilia
Sperm cells use __________ to swim.
flagella
Inside cilia and flagella, microtubules slide against each other with the help of a motor protein called _________.
As a result, the cilium or flagellum bends.
dynein.
The main components of a plant cell wall are _________ and ___________.
cellulose and lignin.
Cell wall functions:
Provide mechanical strength
Regulate volume
Prevent cells from bursting
Role in cell specialization
Plant cells communicate through ____________, channels that pass through the plant cell wall. Nutrients and biochemicals travel through these channels to adjacent cells.
Plasmodesmata
Cells in multicellular organisms must constantly communicate with each other in order for tissues to function.
____________ and ____________ protruding from animal cells are crucial for cell communication.
Proteins and carbohydrates
Animal cells communicate through ______________ , __________________, ______________.
GAP junctions
tight junctions
anchoring/adhering junctions
In ____ __________, proteins form a “tunnel” through the membranes of two neighboring cells, so materials can move through directly.
Allow cells to communicate very rapidly.
GAP junctions
In ________ _________, proteins fuse the membranes of adjacent animal cells together.
They allow sheets of cells to form a leak-proof barrier.
Are like sewing machine stitches.
Tight junctions
____________ ____________ are like rivets.
In these junctions, proteins connect cells to other cells and to the extracellular matrix.
Their proteins reach inside cells and bind to the cytoskeleton, for added mechanical strength.
Anchoring/adhering junctions
______________ orient bacteria to earth’s magnetic field lines.
This allows bacteria to swim vertically through the water, easily adjusting to their optimal oxygen concentration.
“magnetosomes”
