Chapter 4 Flashcards
What did Brown discover?
The nucleus of cells
What did Matthais Schleiden say?
That plants are composed of cells
What did schwann find?
That all animals are composed of cells
What is a cell?
It is the smallest unit of living matter
What did Vrichow discover?
He viewed the human body as a state where each cell is a citizen
What is the cell theory?
1) All organisms are composed of cells
2) cells are the basic units of structure and function in organisms
3) Cells come only from preexisting cells because they are self reproducing
Why do cells need to be so small?
They need to maintain the surface area to volume ratio. Small cells have an adequate surface area for materials exchange
What two types of cells are there?
Prokaryotic and Eukaryotic
What is characteristic of prokaryotic cells?
They are named like this because they lack a membrane bounded nucleus
What are the two different types of prokaryotes?
Archaea and Bacteria
List/Describe the four types of bacteria
- Rod shaped=Bacillus
- Spherical shaped=Coccus
- Long and twisted into spirals=Spirrilla (Rigid ones) or Spirochetes (Flexible)
What does the cell envelop include? (In bacteria)
The plasma membrane, the cell wall, and the glycocalyx
What is the plasma membrane?
It is the phospholipid bilayer with proteins that has the important function of regulating the entrance and exit of substances into/outo of the cytoplasm
In prokaryotes, what does the plasma membrane form?
Mesosomes
What are mesosomes?
They increase the internal surface area for the attachment of enzymes that
What does the cell wall in bacteria do?
It maintains the shape of the cell, even if the cytoplasm should take up an abundance of water. The cell wall in bacteria is strengthened by peptitoglycan
What does teh glycocalyx?
It is a layer of polysaccharides lying outside the cell wall in some bacteria. It can be easily washed off
When the glycocalyx is washed off, what part results?
Capsule. It is a slime layer that ultimately helps to attach to any surface as well as helps the immune system
What is teh cytoplasm?
IT is a semifluid solution that is composed of water and inorganic and organic molecules encased by a plasmma membrane
What kinds of organic molecules are present in the cytoplasm?
Enzymes to help speed up chemical reactions
Where is the DNA of a prokaryote found?
In a chromosome that coils up and is located in a region called the nucleoid
What is a plasmid?
They are extrachromosomal pieces of DNA that a bacteria has
Where is the protein for bacterial DNA syntehsized?
On ribosomes
What are the inclusion bodies, found in cytoplasm?
They store granules of various substances. Some are nutrients that can be broken down when needed
How do cyanobacteria acquire food
They go through photosyntheisis (have thylakoid membranes)
What is the flagella?
They are appendages that allow the bacteria to propel themselves. They are attached to a hook and a basal body. The basl body is a series of rings that is anchored in the cell wall and membrane.
What are fimbriae?
Small bristlelike fibers that sprout from the cell surface. They attach bacteria to a surface
What are conjugation pili?
They are rigid tubular structures used by bacteria to pass DNA from cell to cell
What does the endosymbiotic theory say?
That the mitochondria and chlorplasts (two energy related organelles) arose when the cell engulfed independent prokaryotes
Why does the endosymbiotic theory state what it does?
Because both cholorplasts and mitochondria are bounded by double membranes and contain their own genetic material separate from that in the cell
What does the plant cell wall made up of?
cellulose
What are “compartments” inside a eukaryotic cell called?
Organelles
What do vesicles do?
They carry the products from each organelle around
What is the cytoskeleton?
It is the lattice of protein fibers that maintains the shape of the cell and assists in the movement of organelles
What does the nucleus do that is essential to the life of the cell?
It contains the genetic information that is passed from cell to cell
What does teh nucleus contain?
Chromatin in a semifluid matrix called nucleoplasm
Chromatin condenses to form what?
Chromosomes
What do chromsomes contain?
They contain DNA, protein, and some RNA, as well as Genes
What are genes?
They are units of heredity that are located on the chromosomes
What are the three types of RNA that are produced?
mRNA, tRNA, rRNA
How are ribosomes produced?
rRNA is produced in the nucleolus, a dark region of chromatin where rRNA is joined with proteins to form the subunits of RNA
What do ribosomes do?
They are the site of protein synthesis
What separates the nucleus from teh cytoplasm?
The nuclear envelope
What do the nuclear pores permit?
The passage of ribosomal subunits and mRNA out of the nucleus to the cytoplasm
What happens in ribosomes?
They are particles whrere protein syntehsis occurs. The numbers of ribosomes in cell varies depending on the function
In eukaryotic cells, how do ribosomes move/occur?
Freely within the cytoplasm, each singly or in groups called polyribosomes
What causes a ribosome to bind to the endoplasmic reticulum?
It occurs only if the protein being synthesized by a ribosome.Binding will occur only of the protein that is being synthesized begins with a signal peptide.
What does the endomembrane system consist of?
The nuclear envelope, membranes of the endoplasmic reticulum, the Golgi apparatus, and several types of vesicles
