Biology 224 Liberty University (Dr. Brophy) - Chapter 4
Terms in this set (139)
What are cells?
the fundamental unit of life.
All organisms are composed of Cells.
All cells come from preexisting cells.
Why are cells so small?
cells increase in volume the surface area also increases, but at a lesser rate.
The cell's ________________ determines its metabolic activity.
The cell's _________________ determines the rate of ____________________ into and out of the cell.
surface area, transport
_____________________ is a way of asking and answering questions.
What is technology?
a way of asking and answering questions
Why were microscopes made?
to study cells
makes something LARGER
makes something clearer
uses light passing through the sample to observe objects
What is the resolving power of a light microscope?
200nm (2 x 10-4 mm)
What is a transmission electron microscope?
uses an electron beam passing through the sample to view objects
What is the resolving power of the transmission electron microscope?
0.2nm (2 x 10-7mm)
When is it an appropriate time to use a transmission electron microscope?
cells must be killed and stained with heavy metals to block/scatter the electron. Those that pass through are focused.
How does one use a scanning electron microscope?
coats the surface of a sample with heavy metal stains, then uses an electron beam to scan the surface. Obtain more of a 3D view of the surface.
Domains Eubacteria and Archaea
Lack membrane-bound organelles (e.g. nucleus)
Are simple in structure
Prokaryotic Cells are smaller than Eukaryotic cells.
Describe the structure of the membrane in Prokaryotic organelles?
Describe the function of the membrane in Prokaryotic organelles?
Describe the structure of the nucleotide in Prokaryotic organelles?
Describe the function of the nucleotide in Prokaryotic organelles?
Describe the structure of the cytoplasm in Prokaryotic organelles?
Describe the function of the cytoplasm in Prokaryotic organelles?
Describe the structure of the ribosomes in Prokaryotic organelles?
solid-RNA and Proteins
Describe the function of the ribosomes in Prokaryotic organelles?
Describe the structure of the cell wall in Prokaryotic organelles?
Describe the function of the cell wall in Prokaryotic organelles?
Describe the structure of the capsule in Prokaryotic organelles?
Describe the function of the capsule in Prokaryotic organelles?
Describe the structure of the flagella in Prokaryotic organelles?
Describe the function of the flagella in Prokaryotic organelles?
Eukaryotic Cells (Domain Eukarya):
complex in structure with many organelles
larger in size
In Eukaryotic Cells describe the cytoplasm
an aqueous solution with a lot of proteins
In Eukaryotic Cells the cytoplasm has many proteins that are ___________ controlling a host of ______________.
The enzymes that control reactions, many of these reactions are the first reactions in important Metabolic pathways like
Glycolysis and Fatty Acid synthesis
Describe the cytoskeleton structure.
a series of fibrous organelles which provide an internal skeleton to cells, and perform some other functions as well.
In the cytoskeleton, each of the three types of fibers are constructed from many-----------------------.
Describe the structure of microtubules.
larger, long hollow tubes of Tubulin contributing to the cytoskeleton
___________________________ have two differently charged ends.
In Microtubules, what controls their growth from one point to another?
Centrioles and Basal Bodies
____________________ form cellular "roads" along which vesicles and chromosomes move using molecular " motors."
What is the name the motor protein found in Microtubles?
Microtubules forms what for cellular locomotion?
Cilia and Flagella
Microtubules forms what for moving chromosomes during cell division?
What cell division are Microtubules apart of?
There are how many Intermediate Filaments?
more than 50 different types
What is the structure of Intermediate Filaments?
thin rods of Keratin
Intermediate Filaments are more stable than other elements of cytoskeleton.
What is the function of Intermediate Filaments?
Maintain cellular shape and provide mechanical strength to cells.
Lines the inside of the Nuclear Membrane to anchor Nuclear Pores.
Smallest; thin rods of Actin.
_________________ can exist as single filaments, in bundles or in networks.
What are the functions of Microfilaments?
- cellular movements
-cytoplasmic division (cytokinesis) to divide a cell into two daughter cells following Mitosis and Meiosis.
- occurs near the plasma membrane and anchor other proteins
- supports the Plasma Membrane and provide shape and strength to the cell.
What are examples of cellular movements in Microfilaments?
- Muscle contraction
- Cytoplasmic streaming
- Pseudopod formation
Describe the structure of the Nucleus?
What is the function of the nucleus?
stores DNA- hereditary information.
The nuclear membrane contains thousands of ____________________ which regulate ___________ between the Nucleus and the Cytoplasm.
small pores, transport
In the nucleus, pores are surrounded by a complex of _____ large protein______.
Proteins that are for the Nucleus have a short peptide _______________________
Nuclear Localization Signal
What consists of the gene(s) which code for ribosomal RNA?
Why are a rRNAs needed ?
for ribosome construction
What are not technically "organelles"?
Describe the structures of Organelles.
Large and small solid subunits
Ribosomes are composed of how many rRNAs?
Ribosomes are composed of how many Proteins?
Eukaryotes with __________ proteins per subunit.
What is the function of Ribosomes?
Where are Ribosomes found?
free in cytoplasm, attached to the Endoplasmic Reticulum, or inside Mitochondria and Chloroplasts.
The ___________________ is a group of functionally interrelated organelles.
What does the Endomembrane System include?
- Endoplasmic Reticulum
- Golgi Apparatus
- Plasma Membrane
What is the structure of the Endoplasmic Reticulum?
Single membrane surrounding a central lumen
What can compose of up to 10% of the cell's total volume?
studded with ribosomes
How do ribosomes synthesize proteins?
which are transported into the lumen of the ER, segregating them from the Cytoplasm.
The proteins in the ER can be ________________________ to alter their functions.
ERs are "tagged" with a short peptide signal to mark them for delivery to various organelles by vesicles.
Some of the proteins in the ER have an oligosaccharide chain attached and form _____________
What is the function of the Rough ER?
synthesize glycoproteins, membrane-bound proteins, and proteins destined for various organelles.
What lacks ribosomes and is more tubular than flattened sacs?
Detoxification of various poisons taken into the body, by modifying them to be more polar and easier to excrete from the cell.
The smooth ER contains enzymes necessary for ____________ and _______________ metabolism.
Glycogen and Calcium
The Smooth ER synthesize ___________ for membranes, and other _____________ including steroid hormones.
Phospholipids and lipids
What is the structure of the Golgi Apparatus?
Flattened sacs( single membrane surrounding central lumen)
__________________ transport Proteins from the ER to the cis to medial to trans regions of the Golgi.
What are the functions of the Golgi Apparatus?
-add/or modify carbohydrates portion of Glycoproteins.
What is the function of Proteases in the Golgi Apparatus?
cut large proteins into smaller, functional proteins.
What is the function of Secretion in the Golgi Apparatus?
packages materials into secretory vesicles to be released from cell
___________________________ concentrate, package and sort proteins before being transported to cellular destinations
What is the structure of Lysosomes?
Large vesicles containing digestive enzymes (Glycoproteins), surrounded by a single membrane.
What is the function of Lysosomes?
Digestion via Hydrolytic Reactions.
How are Primary Lysosomes formed?
formed by vesicles containing Hydrolytic Enzymes forming from the Golgi.
How are secondary lysosomes formed?
by the fusion of a primary Lysosome and a food vacuole.
What is the name of the food vacuole found in the secondary lysosome?
Describe the function of the vacuoles.
similar to Large Vesicles
What are the functions of the vacuols?
- storage of food or waste materials
- maintain turgor pressure
Freshwater Protists use them to excrete excess water.
Describe the structure of Microbodies.
What is the function of Microbodies?
contain enzymes for specific functions
What includes peroxisomes and glyoxysomes?
Contain catalase to degrade Hydrogen Peroxide.
How are Peroxisomes synthesized?
as vesicles from the ER.
Found primarily in plant seeds.
Converts stored lipids into Carbohydrates for growth.
_____________________ is a part of the Endomembrane System.
What are the functions of the Plasma Membrane?
- Membrane Transport
- Cell Signaling
- Cell Adhesion
The Mitochondria and Chloroplasts can divide independently of the cell, and also contain their own _________________ and _____________________.
What is the structure of the Mitochondria?
What is the function of the Mitochondria?
convert energy in organic molecules into ATP.
The conversion of energy in organic molecules into ATP is known as
Where does cellular respiration begin?
in the cytoplasm with glycolysis
What are the final stages of Cellular Respiration?
Krebs Cycle and Electron Transport
The end product of cellular respiration is
What is a modified nucleotide that has a high energy content?
What energy source is used to do most types of cellular work?
What is the structure of the Chloroplast?
Three Membranes (inner, outer and thylakoid)
What is the function of the Chloroplast?
Chloroplasts contain the photosynthetic pigments, embedded within internal stacks of membranes called_____________.
Thylakoid membranes are distinctive, only ___________are phospholipids.
The fluid surrounding the Thylakoid is the _______________.
Produce and store various carotenoid pigments producing red, yellow and orange colors in flowers and fruit.
What is the function of Leukoplasts?
store food (starch and fats)
Describe the structure of the plant cell wall.
thin mat of cellulose fibers
What is the function of the cell wall?
-support the cell
-limits the volume of the cell to help maintain Turgor Pressure
- forms a barrier to prevent infection by Fungi and Bacteria
Describe the structure of the Extracellular Matrix.
Interwoven mat of fibrous protein such as Collagen, a matrix of Glycoproteins( Proteoglycans), Proteins which link the others together into a continuous unit.
What is the function of the Extracellular Matrix?
help connect adjacent cells together
What is an advantage of Eukaryotic Cells?
the large number of organelles they contain
Most proteins are synthesized on ________________ in the _____________________.
Many proteins take the first step in being sorted to ___________ when they are being translated.
In Cotranslation Sorting, the first 12-20 amino acids are _______________ and form an ______________.
non-polar, ER Signal Sequence
In Cotranslation Sorting, a special protein, the _______________ finds and binds the Signal (Hydrophobic amino acids).
Signal Recognition Protein
In Cotranslation Sorting, the Signal Recognition Protein drags the _________________________ to the ER an attaches to the Signal Recognition Protein Receptor.