Biology - Chapter 3
Scanning electron microscopes
Beam electrons over a metal-coated specimen
Scanning electron microscopes
Bounce electrons off the outside of a metal-coated three-dimensional object to observe the exterior texture
Eukarya
Key genetic sequences suggest that archaea are more closely related to members of domain _________ than they are to members of domain bacteria
Less surface area relative to volume
Less efficient exchange of materials between cell's interior and exterior Large cell sizr
Cell membrane
Lipid-rich boundary between the cells and outside environment
Smooth endoplasmic reticulum
Lipids, detoxifying enzymes, and membrane components are produced and stored in the ______ ____________ ___________
Cell parts in the endomembrane system
Lysosomes; Golgi apparatus; nuclear envelope; endoplasmic reticulum
Microtubules
Main component of the cytoskeleton which is composed of tubulin protein subunits and is used in cell division and transportation within cells
Vesciles
Membranous spheres that transport materials inside the cell as part of the endomembrane system
More surface area relative to volume
More efficient exchange of materials between cell's interior and exterior Small cell size
Mitochondrion
Cellular respiration extracts energy from food and takes place in the organelle called a(n)
Animal crll
Centrioles present; chloroplasts absent
Gap junctions
Channels for the exchange of substances between adjacent animal cells
Nucleolus
Dense spot in the nucleus where components of RIBOSOMES are assembled
Membrane lipids; key genetic sequences
Differences between domains Bacteria and Archaea
Food vacuole in amoebas
Digest nutrients engulfed by cell
Cell membranes
Enclose organelles in eukaryotic cells; separate cytoplasm and cell's surroundings; receive and respond to external stimuli
Organelles; cytoskeleton; ions and enzymes
Found in the cytoplasm, outside the nuclear membrane.
Amoebas have extensions of their cell membrane Red blood cells have a flattened and thin shape Nerve cells are long and thin
How do cells increase their ratio of surface area to volume?
DNA; proteins
In a cell, ___ is the genetic information of the cell, and RNA plays a role in the production of ________
Tight junctions
In animal cells, cell junctions called _____ ________ form barriers between cells that prevent leaking of fluids and water-soluble molecules
Nucleus
In eukaryotic cells, the DNA that specifies the proteins of the cell is stored in a membrane-bounded organelle called thr
3 components of the cell theiry
1. The cell is the fundamental unit of all life 2. All organisms are made of one or more cells 3. All cells originate from preexisting cells
Nucleoid
In prokaryotic cells, DNA congregates in an area called the
nucleus
A eukaryotic cell is different from a prokaryotic cell in that it contains a _______
O2 and CO2, small nonpolar molecules, and lipids
Able to pass freely through the phospholipid bilayer
Cytoplasm
All cell contents except the nucleus
Membrane
All cells have a cell ________ surrounding the cytoplasm and forming a boundary between the cell and its environment
Outside environment
All cells surrounded by cell membranes, also called plasma membranes, that separate the cytoplasm from the
Large leaves in a light-poor environment Large surface area in fish gills
In what cases us high surface area advantageous to an organism?
Cells
All living things consist of one or more _____
Bacteria
Small cell size, fatty acids in the cell membrane, cell wall present in most
Archaea
Small cell size, nonfatty acid lipids in the cell membrane, cell wall present in most
Larger than
Small objects have a surface area to volume ratio _________ ______ that of large objects
Endoplasmic reticulum
Network of membranes originating at the nuclear envelope and wining through the crll
Cytoskeleton
Network of proteins that provide a structural framework within the cell 3 types of protein filaments comprise THIS
Cytoskeleton
Network of proteins that provide a structural framework within the crll
Chloroplasy
Organelle that is the site of photosynthesis in plant cells. A type of plastid.
Membranes
Organelles carry out specialized functions in the cell and are enclosed by _________
Mitochondria and chloroplasts
Organelles that are thought to have arisen by endosymbiosis
Peroxisomes
Organelles that originate in the ER and contain enzymes that dispose of toxic substances
Transmission electron microscopes
Pass electrons through a specimen
Light microscope
Passes light through a transparent or thinly sliced specimen to generate true-color views of cells
Hydrophilic
Phosphate end of a phospholipid, meaning its polar covalent binds attract water.
Transport vesicles
Pinched off the Golgi apparatus and will deliver their contents to another part of the crll
Vacuoles
Plant cells have large central ________ where water, salts, and sugars are stored and where materials are broken down and recycled with enzymes similar to lysosomes in animal cells.
Drawbacks of electron microscopy
Specimens must be killed prior to viewing them The microscopes are expensive All images are black and white
Eukarya
Possible larger cell size, fatty acids in the cell membrane, cell wall present in some
Cell theory
States that all life is composed of one or more cells, which are the fundamental units of all life
Cytoskeleton functions
Structural support; transportation; aids cell division
Ribosome on the rough ER
Proteins become part of the cell membrane or are secreted from the cell
Free-floating ribosome
Proteins remain in the crll
Components of cell membranes
Proteins, phospholipids, steroids
Contractile vacuole in Paramecium
Pump excess water out of the cell
True
T/F Almost all cells have a small size less than 0.1mm in diameter
Hydrophobic
Tails of a phospholipid, face away from the water.
Cell
Simplest and most basic unit of life and can function as one or many working together
Prokaryotic cells
Simplest forms of life and lack a nucleus
Ribosome
Site of protein production
Nucleoid
The area within the cytoplasm of a prokaryotic cell where the circular DBA molecule is found is called the ________ and is not bounded by a membrane
Phospholipid
The cell membrane is composed of a type of lipid called THIS. Has 2 fatty acids and a phosphate group extending from a glycerol molecule.
Ribosome
The cell structure that manufactures proteins
Enzymes
The digestive _______ that end up inside lysosomes are made in the rough ER, and then the Golgi Apparatus packages them into vesicles, forming lysosomes.
Endomembrane
The internal membranes of several organelles are interconnected and form the ______________ system of a eukaryotic cell
Cilia
The paramecium is able to move through its watery environment with the thousands of _____ on the outside of its body.
Cell wall
The rigid ____ ____ of most bacterial cells surrounds the cell membrane, protecting the cell and giving the cell shape
Plastids (plant organelles)
They contain their own DNA and ribosomes Some assemble and store starch Some, such as chloroplasts, synthesize pigmentd
Confocal microscope
White or laser light is focused through a lens, and the image passes through a pinhole
Anchoring junctions
Connect adjacent animal cells by linking their intermediate filaments in one place, like "spot welds"
Anchoring junctions
Connect animal cells to the extra cellular matrix or to adjacent animal cells in one place
Central vacuole in plants
Contains enzymes, salts, pigments, sugars, and acids
DNA
Contains genetic information
Plasmodesmata
Cytoplasm can flow between adjacent plant cells through special openings in the cell wall called ____________
Present in all types of both prokaryotic and eukaryotic cells
Cytoplasm, RNA, ribosomes, DNA
Steps for making a membrane protein for a eukaryotic cell
1. In the nucleus, genes in the DNA encode the membrane protein are copied into a messenger RNA (mRNA). 2. The mRNA exits the nucleus through nuclear pores of the nuclear envelope. 3. The mRNA binds to a ribosome of the rough ER and produces a protein, which exits the ER in a vesicle. 4. The vesicle delivers the protein to the Golgi apparatus, where the protein folds and is packaged in a vesicle for export from the cell. 5. The vesicle fuses with the cell membrane and releases the protein into the membrane surface
Small; large
A ______ cell can exchange materials with the environment more efficiently than a ______ cell can
Plant cell
Chloroplasts present; central vacuole present
Mitochondrion
Functions in the production of cellular energy
Impart shape; prevent the cell from bursting; regulate cell volume
Functions of the cell wall
Tight junctions
Fuse cell membranes of adjacent animal cells, forming a barrier
Bacteria; plants; archaea; fungi; algae
Groups have cells with cell walls
Bacteria
Important decomposers and producers; some live in human intestines and help with digestion; earth's oldest organisms; some are used to make pharmaceuticals
Plasmodesmata
Tunnels for the exchange of substances between adjacent plant cells