A&P: The cytoplasm of the cell

Quizlet Annie Song

cytosol and organelles

Cytoplasm contains two portions:

Cytosol

-55% of volume of the cell

-contains water (75-90%) & dissolved and suspended components

Metabolic reactions

Cytosol is the site for many __________________ of the cell

1. Microfilaments

2. Intermediate filaments

3. Microtubules

Cytoskeleton of the Cytosol is formed by 3 protein filaments:

actin & myosin

Microfilaments include the ______________ and _____________

-muscle contraction

-cell division

-cell locomotion

Microfilaments help generate movement for:

-anchoring cytoskeleton to integral proteins

-support for microvilli

Microfilaments provide mechanical support for:

Intermediate filaments

Exceptionally strong filaments that:

-located in parts of the cell subjected to mechanical stress

-keep organelles in position

-help attaching cells to one another

Microtubules

Hollow tunes made of tubulin:

-help determining cell shape

-movement of organelles, chromosomes, cilia, flagella

Organelles

Specialized functional compartments within the cell

Functions of the cell

Number and types of organelles depend on the:

Centrosome

Located near the nucleus which consists of:

-2 centrioles & perecentriolar material

-growing of mitotic spindle in reproduction

-formation of Microtubules in non reproducing cells

What's the functions of the centrosome?

Cilia and flagella

Moving projections composed of Microtubules

Cilia

-move in coordination of the surface of cells

-help sweeping foreign particles out of (find in airway)

Flagella

Have similar structure with cilia but singular and much longer

-move the entire cell

-only present in the sperm cell

Ribosomes

The site for the synthesis of proteins

-contain the rRNA

-formed by 2 subunits (small and large)

Rough ER

Some ribosomes are attached to _______________ for synthesize proteins for organelles, membrane, or "export"

Cytoplasm

Some free ribosomes are found in __________ for synthesize proteins to be used in the Cytosol or for other organelles

Endoplasmic Reticulum (ER)

Network of flattened sacs and tubules extending from the nuclear envelope

-more than 50% of membranous surfaces in the cell

Rough ER

-studded with ribosomes for the synthesis of proteins

-produces secretory, membrane, and organelle proteins

Smooth ER

-extends from the rough ER, but not studded with ribosmomes

-has many enzymes for the synthesis of fatty acids and steroids (lipids)

-release free glucose, Ca2+

Golgi complex

Small stack of flattened sacs close to the nucleus

-produces secretory products and lysosomes

-synthesized proteins are transported here

-secretory cells have extensive amount of this

Lysosomes

Membrane-enclosed vesicles formed in the Golgi complex

-contain digestive and hydrologic enzymes at pH5

-digest the contents of endosomes, phagosomes, and pinochtic vesicles

-digest worn out organelles and entire cells

Mitochondria

Generate most of the ATP through the aerobic glycolysis

-more abundant in active cells

-self-replicate, have their own DNA inherited only from the mother

Perixisomes

-microbodies containing oxidases

-eliminate toxic metabolic byproducts

-can self-replicate

Proteasomes

-very tiny, discovered recently

-contain enzymes for degrading unneeded, damaged, or faulty proteins

-"cut" proteins into smaller pieces for other enzymes to break them down into amino acids

Nucleus

-usually most prominent feature of the cell

-most cells have one, but some more than one, or none

Double membrane (two lipid-bilayers) with pores

The nuclear envelope consists of:

wider

The nuclear pores are 10 times _________ than plasma membrane's

small molecules and ions

What can pass through the nuclear pores through diffusion?

RNA and proteins

What can pass through pores by active transport?

Nucleolus

Clusters of proteins, DNA, and RNA not enclosed by a membrane

Ribosomes

Nucleolus produce the __________

cell division

Nucleolus dispersed during _______________ and recognized afterward

gene; chromosomes

Nucleus contains the ___________ aligned in he ___________

Chromosome

One DNA molecule coiled with proteins

Chromatin

DNA with the proteins and some RNA

Genome

Total genetic information carried by one cell

46 (23 from each parent)

How many chromosomes are found in human somatic cells?

Nucleotides

DNA and RNA are chains of repeating monomers called

1. Nitrogenous base

2. Pentose sugar

3. Phosphate group

Each nucleotide consists of three parts:

A-T G-C

Nitrogenous base paring for DNA

A-U G-C

Nitrogenous base paring for RNA

DNA

______________ contains detailed plans for each protein the cell needs

three-nitrogenous base sequence

Each amino acid is coded by a ______________________ in the DNA

Codon

Each combination of three nitrogenous bases within the DNA

Nucleus; cytoplasm

DNA is always in _____________, yet proteins are synthesized in _____________

Transcription

DNA directs the synthesis of proteins by producing special copies of its code in the form of functionally distinct RNA

-first step of protein synthesis

-occur in nucleus and the copies transported out of the nucleus into cytoplasm by RNA

Where do transcription occurs?

mRNA

Directs the synthesis of the protein

rRNA

Joint ribosomal proteins to make ribosomes

tRNA

Binds to one amino acid on one end and holds it in place on a ribosomes until incorporated into a protein. On the other end it has an anticodon complementary to the specific codon of mRNA

Promoter

A special codon of DNA located near the beginning of gene that begins the transcription process

Terminator

A special codon of DNA that specifies the end of gene that ends the transcription

Exons

The part of the gene that code for parts of proteins

Introns

Between exons and do not code for any part of the protein

pre-mRNA

The RNA formed in the transcription process

Final functional mRNA

Formed after enzymes cut out the introns and splice together the exons from the pre-mRNA

Alternative Splicing of mRNA

Produces many more different mRNAs than available genes in the DNA

-one gene may code for 10 or more different proteins

Chemical modification

Occurs in Golgi complex

-one protein can produce two or more different proteins

Translation

The nucleotide sequence of the mRNA specifies the sequence of amino acids in the primary structure

ribosomes within cytoplasm

Where does translation occurs?

mRNA

Small subunit of the ribosomes has a binding site for:

tRNA

The large subunit has 3 binding sites for:

P (peptidyl) site

For tRNA carrying the growing polypeptide chain

A (aminoacyl) site

For the tRNA carrying the next amino acid to be added

E (exit) site

Binds tRNA before releasing

Initiator-tRNA

Binds to the small subunit of the ribosomes to start codon (AUG) on the mRNA

AUG(methonine)

Which amino acid is always the first in a growing peptide chain?

Rate of translation

15 peptide bonds per second

the same time

Several identical proteins may be assembled at _________________

Stop codon

Protein synthesis ends when the ribosome reached a _____________ at the A site

-completion protein detaches from the final tRNA

-tRNA vacates the P sire

-the ribosome splits back into its large and small subunits

When translation reaches one stop codon: