describe a nerve cell
long, threadlike extensions that transmit electrical impulses from one part of the body to another.
which 3 parts are easily seen under a microscope when looking at a cell?
the nucleus, cytoplasm and cell membrane
what are inside the cytoplasm?
what's the structure of the nucleus and what's its function?
- -nuclear membrane
- -contents -> nucleolus (nucleoli)
- -DNA which forms the chromosomes
- to controll the cell processes by protein synthesis
- contains genetic information
what's the function of the cell membrane?
to determine (ID) which substances (cells) enter or leave the cell. It also maintains cell integrit. Also used for communication, selective transport.
what are the characteristics of the cell membrane? what's its nickname?
extremely thin and flexible. selectively permeable (only allows certain things to enter/leave.)
what's the structure of the cell membrane?
it's composed ot lipids, proteins and carbohydrates.
Picture an endoplasmic reticulum. what's its function?
- (membrane walled canals)
- provides a tubular network that transports molecules from one cell part to another. forms mini circulatory systems.
what's included outside of the ER? what type of ER if these are included?
ribosomes . Rough ER.
what's the purpose of the ribosomes and what are they composed of?
protein synthesis and will also exist independently around the cytoplasm. they're composed of protein and RNA molecules.
what's about the smooth ER? what's its job?
contains enzymes which is important for lipid synthesis, absorption of fats and metabolism of drugs. sounds like liver cells need them most.
Sooo anyways.... the proteins being made by the riboseomes are moved through the ER. now what?
It moves on to the golgi apparatus.
picture the golgi apparatus. What's its purpose?
- (layers of sacs near nucleus)
- refines, packages and delivers proteins synthesized on ribosomes.
- forms glycoproteins and package products.
how do these proteins look like when they arrive at golgi apparatus city? do they change? how?
enclosed in vesicles composed of the ER membrane. yes, they become chemically modified and by the end of the golgi apparatus, they are then packaged in bits of GA membrane.
picture a mitochondria. what's its purpose?
- (sausage like sacs with cristae)
- energy from certain nutrient molecules will be transformed into adenosine triphosphate (ATP) which is energy that the cell can use.
- ATP if formed by cellular respiration
name an active cell which contain many thousands of mitochiondria?
the muscle cell.
what's a lysosome?
they're the garbage disposals of the cell. they contain powerful enzymes which break down nutrients of foreign particles.
give an example of a lysosome using white blood cells.
a white blood cell detects a foreign object. it engulfs it andh they become digested with the lysomal enzymes.
they also destroy worn cellular parts
what's a centrosome?
- paired group of tiny cylinders (centriols)
- function: makes spindle during mitosis
what are cell fibers?
- microfilaments: support organelles in lattice
- microtubules: bigger in lattice
what's the microvilli, cilia and flagellum?
- Microvilli: cytoplasmic extensions to increase surface area
- Cilia: made of microtubules
- Flagellum: single tail-like structure for movement.
what's that one important equation?
- C6H12O6+6O2 -> 6CO2+6H2O + ATP
- (glucose)+(oxygen) -> (Carbon dioxide)+(water)+(energy)
what is the DNA structure composed of?
- nucleotide which has
- 1. phosphate group
- 2. sugar group
- 3. nitrogen base: purines and pyrimidines
steps for DNA replication
- 1. DNA unzips
- 2. complimentary nucleotides match up
- 3. results in two identical copies
name the organic bases in a DNA molecule.
adenine (A), thymine (T), cytosine (C), guanine (G)
what does the sequence: G, G, T in a DNA strand represent?
one type of amino acid.
What does transcription do?
since DNA molecules are within a cell's nucleus and when protein synthesis occurs in the cytoplasm, genetic information needs to be carried from the nculeus to the cutoplasm.
what does messenger RNA (mRNA) do?
helps accomplish the task of transfering the information through transcription.
what's the difference between RNA and mRNA?
RNA is a nucleic acid and mRNA is a type that carries a gene's message.
how do RNA molecules differ from DNA? similarities?
- -single stranded, nucleotides contain ribose rather than deoxyribose sugar.
- -RNA carry uracil instead of thymine.
- -double stranded, nucleotides contain DEOXYribose.
- -DNA carries thymine and not uracil.
- -both have guanine, cytosine and adenine.
what does the RNA polymerase do?
synthesized mRNA and it somehow "knows" which strands contain information. it knows where the genes begin or stop and knows the correct direction of the DNA.
what are codons?
three base sequence.
how is the process of protein synthesis completed? what must the mRNA do?
mRNA has to leave the nucleus and associate with a ribosome. in order for that to happen, series of codons on mRNA needs to be converted from the "language" of nucleic acids to the "language" of amino acids. this is called TRANSLATION!
what does the transfer RNA (tRNA) do?
correctly align amino acids to form proteins.
at least how many tRNA's should be available? why?
20 because at least 20 different types of amino acids form biological proteins, at least twenty different types of tRNA needs to be free.
soo the tRNA carried 3 sets of nucleotides right? what are those called?