Unit 4 Flashcards
Why do cells have a minimum limit?
Must have space for enough DNA, protein molecules, and organelles to survive & reproduce
Why do cells have a maximum size limit?
- Must have enough SURFACE AREA to obtain adequate nutrients and O2 from the environment and dispose of wastes
- Also limited by the distance that these materials will diffuse within the cell
Cells need a large enough ______:______ ratio.
surface area : volume
Most cells are ______.
Microscopic
Our knowledge of cells depends on the development of what?
The microscope
What is magnification?
The increase in the apparent size of the object
What is resolution?
- The clarity of an image
- The ability to see 2 close objects as separate
How does the light microscope work?
By passing visible light through a specimen
When was the light microscope first used?
1665
Who discovered cells?
Robert Hooke
By mid-1800s discoveries from light microscopes led to the _______.
Cell theory
What is stated in the cell theory?
- all living things are made of cells
- all cells come from other cells
To what degree can LMs magnify and resolve?
Magnify: about 1000x
Resolve: as small as 0.2 micrometers
When was the EM first used?
1950s
How does an EM work?
Uses beam of electrons to image specimens that have been sliced thin and coated with a thin film of metal
Which had better resolution: EM or LM?
EM was much better
EM helped to discover cell _______.
Ultrastructure
EMs cannot be used to study _________.
Living specimens
2 types of electron microscopes are: ____&____.
Scanning EM and Transmission EM
What does the scanning EM do?
Study detail of cell surfaces
What does the transmission EM do?
Study detail of internal cell structure
2 different types of light microscopy:
Differential interference-contrast
and
Fluorescent confocal
What does differential interference-contrast do?
- Can see density differences
- Can use living specimen
What does fluorescent confocal do?
Specific molecules are tagged with fluorescent dyes
What are the 4 life processes in eukaryotic cells that depend on structures and organelles?
- Manufacturing
- Breakdown of molecules
- Energy processing
- Structural support, movement, communication
What organelles is manufacturing dependent on?
Nucleus, Ribosome, ER, Golgi apparatus
What organelles is breakdown of molecules dependent on?
Lysosomes, Vacuoles, Peroxisomes
What organelles is energy processing dependent on?
Mitochondria, Chloroplasts
What organelles are structural support, movement, and communication dependent on?
Cytoskeleton, Cell wall, Plasma membrane
Lysosomes and centrioles are NOT found in ____ cells.
Plant
A rigid cell wall, chloroplasts, and a central vacuole are not found in _____ cells.
Animal
______ form a 2 layer sheet called the _______.
Phospholipids, phospholipid bilayer
_______ heads face outward, toward the H2O.
Hydrophilic
______ tails face inward, away from the H2O.
Hydrophobic
What are attached to the surface of/sometimes embedded in the phospholipid bilayer?
Proteins
The _____ controls the cell’s activities and is responsible for inheritance.
Nucleus
_____ makes up chromosomes.
Chromatin
Inside of the ______ is a complex of proteins and DNA called chromatin.
Nucleus
What is copied in the nucleus prior to (in order for) cell division?
DNA
What is the nuclear envelope?
Double membrane with pores that allow material to flow in and out of the nucleus
The nuclear envelope is attached to the _____, a network of cellular membranes.
Endoplasmic Reticulum
What makes the cell’s proteins?
Ribosomes
Ribosomes are made in the _____.
Nucleolus
which is inside the nucleus
Cells that must _____ have a lot of ribosomes.
create lots of protein
Ribosomes may be _____ or _____.
free or bound
_____ ribosomes: suspended in the cytoplasm
free
_____ ribosomes: attached to the ROUGH ER
bound
The membranes within a eukaryotic cell are physically connected and compose the _____.
Endomembrane system
Which organelles make up the endomembrane system?
Nuclear envelope, ER, Golgi, Lysosomes, Vacuole, Plasma membrane
_____ ER lacks ribosomes.
Smooth
_____ ER: synthesis of lipids; detoxification of drugs/poisons
Smooth
_____ ER has ribosomes.
Rough
_____ ER: synthesis of additional membrane for itself and proteins
Rough
Transport vesicles take products from the _____ to the _____.
ER to the Golgi
Products are modified as they move through the _____.
Golgi
What is a membranous sac containing DIGESTIVE enzymes?
Lysosome
_____ isolates potent enzymes from the rest of the cell.
Lysosome membrane
Lysosomes _____ or _____ damaged parts of a cell.
Remove, Recycle
What are vacuoles?
Membranous sacs with a variety of functions:
- Central vacuole in plants
- Pigment vacuoles in plants provide color to flowers
- Contractile vacuoles (in some protists) expel water from the cell
2 functions of peroxisomes:
- Breaks down lipids
- Detoxification of harmful substances
Peroxisomes are similar to the _____.
Smooth ER
Cellular respiration occurs in the _____.
Mitochondria
_____ converts chemical energy in foods to chemical energy in ATP
Cellular respiration
Mitochondria have _____ internal compartments.
2
Chloroplasts are the sites of _____ within plant cells
Photosynthesis
Photosynthesis converts _____ energy to _____ energy of sugar molecules
Light, Chemical
Chloroplasts have these 2 compartments within them:
- Stacks of grana
- Cytoplasm-like stroma
What is a network of protein fibers that extend throughout the cytoplasm?
Cytoskeleton
How does the cytoskeleton function like a support skeleton?
By providing
- structural support
- cell motility
What are the 3 types of cytoskeleton fibers?
- Microfilament
- Intermediate filament
- Microtubules
Solid rods, composed mainly of globular actin proteins, arranged in a twisted double chain
Microfilament
Made of various fibrous proteins composed in a ropelike structure
Intermediate filament
Straight, hollow tubes composed of globular tubulin proteins
Microtubules
2 functions of microfilaments
- Support the cell’s shape
- Involved in motility
2 functions of intermediate filaments
- Reinforce cell shape
- Anchor organelles
2 functions of microtubules
- Shape the cell
- Act as tracks for motor protein (cilia & flagella)
_____ and _____ both aid in cell locomotion
Cilia and Flagella
Short, numerous, work together like coordinated oars of a rowing team
Cilia
Longer, limited to one or a few per cell, propel the cell in a whip-like motion
Flagella
What line the respiratory tract and act to sweep debris out?
Cilia
What are part of sperm cells, allowing them to propel forward?
Flagella
Cilia and flagella move when _____ bend.
Microtubules
_____ and _____ are made of microtubules wrapped in an extension of the plasma membrane.
Cilia and Flagella
What is the ratio of
microtubule doublets : central microtubules?
9 microtubule doublets : 2 central microtubules
The 9 + 2 pattern of surrounding and central microtubules are anchored in a _____.
Basal body
