Normal Cell Structure (P) Flashcards
What is cell?
It is the basic structural and functional unit of life
What is the characteristic of cell?
Each cell is a highly organized unit
What is cytoplasm?
It is the mat bet the plasma membrane and nucleus
What is the characteristic and function of nucleus?
It contains the cell’s genetic mat and directs cell acts
What is the characteristic of cellular organelles?
Each performs sp functions
What are the functions of plasma membrane?
1) It forms the outer boundary of the cell
2) It plays a dynamic role in cellular act
3) It encloses the cell
4) It supports the cell contents
5) It is a selective barrier that regulates what goes into and out of the cell
6) It plays a role in communication bet cells
7) It separates intracellular substances from extracellular substances
What are intracellular cells?
The cells inside
What are intercellular cells?
The cells in bet
What is the characteristic of protein molecules?
These float among the phospholipid molecules
What are the functions of membrane proteins?
Membrane proteins functions as:
1) Marker molecules
2) Attachment proteins
3) Transport proteins
4) Receptor proteins
5) Enzymes
What are the exs of attachment proteins?
1) Cadherins
2) Integrins
What are the components of cytoplasm?
1) Half cytosol
2) Half organelles
What are the characteristics of cytosol?
1) It is the fluid part of the cytoplasm
2) It contains the cytoskeleton and cytoplasmic inclusions
What are the purposes of cytoskeleton?
1) It supports the cell
2) It enables cell movements
What are the components of cytoskeleton?
1) Microtubules
2) Actin filaments
3) Intermediate filaments
What are the purposes of microtubules?
1) It provides support
2) It aids in cell division
What are microtubules?
These are the components of organelles
What are the purposes of actin filaments?
1) It supports the plasma membrane
2) It defines the shape of the cell
What is the purpose of intermediate filaments?
To provide mechanical support to the cell
The cytoplasm is a what type of fluid?
Intracellular fluid
What are cytoplasmic inclusions?
These are aggregates of chemicals either produced by the cell or taken in by the cell
What are the exs of cytoplasmic inclusions?
1) Lipids
2) Glycogen
3) Hgb
4) Melanin
What is the characteristic of nuclear envelope?
It consists of 2 separate membranes w/ nuclear pores
What is the purpose of nuclear envelope?
It encloses the jellylike nucleoplasm
What are the characteristics of nucleoplasm?
1) It is jellylike
2) It contains essential solutes
Where are DNA and associated proteins found?
These are found in the nucleus
What are the characteristics of DNA?
1) It is the hereditary mat of the cell
2) It contains the genetic library w/ blueprints for nearly all cellular proteins
What are the functions of DNA?
1) It controls the acts of the cell
2) It dictates the kinds and amts of proteins to be synthesized
Bet cell divisions, the DNA is organized as what?
As chromatin
What happens during cell division?
The chromatin condenses to form chromosomes
What are the characteristics of chromosomes?
1) It consists of 2 chromatids
2) The 2 chromatids are connected by a centromere
What are the subunits that made up microtubules?
Tubulin subunits / tubulin protein subunits
What is the size of microtubules?
25 nm in diameter w/ 5 nm thick walls
What type of subunits made up actin filaments?
Actin subunits
What is the other term for actin filaments?
Microfilaments
What is the size of actin filaments?
8 nm in diameter
What type of subunits made up intermediate filaments?
Protein subunits
What are intermediate filaments?
These are protein fibers
What is the size of intermediate filaments?
10 nm in diameter
What are cytoplasmic organelles?
These are specialized subcellular structures w/ sp functions
What are the 2 types of cytoplasmic organelles?
1) Membranous
2) Nonmembranous
What are the cytoplasmic organelles that are membranous?
1) Mitochondria
2) Peroxisomes
3) Lysosomes
4) ER
5) Golgi apparatus
What are the cytoplasmic organelles that are nonmembranous?
1) Centrioles
2) Ribosomes
What are the characteristics of nucleoli?
1) These are the dark-staining spherical bodies within the nucleus
2) It consists of RNA and proteins
3) It is the site of ribosomal subunit assembly
What is the purpose of nucleoli?
It produces ribosomal ribonucleic acid (rRNA)
What are ribosomes?
These are the sites of protein synthesis
What are the 2 types of ribosomes?
1) Free ribosomes
2) Attached ribosomes
What are free ribosomes?
These are ribosomes that are not attached to any organelles
What is the function of free ribosomes?
It synthesizes proteins used inside the cell
What are attached ribosomes?
These are part of a network of membranes called the RER
What is the function of attached ribosomes?
To produce proteins that are secreted from the cell
What is the process (or steps) of how ribosomes are produced?
1) Ribosomal proteins, produced in the cytoplasm are transported through nuclear pores into the nucleolus
2) rRNA, most of w/c is produced in the nucleolus, is assembled w/ ribosomal proteins to form small and large ribosomal subunits
3) The small and large ribosomal subunits leave the nucleolus and the nucleus through nuclear pores
4) The small and large subunits, now in the cytoplasm, combine w/ each other and w/ mRNA during protein synthesis
What is ER?
These are series of membranes forming sacs and tubules that extend from the outer nuclear membrane into the cytoplasm
What are the 2 varieties of ER?
1) RER
2) SER
What are the characteristics of RER?
1) It is studded w/ ribosomes
2) It is the major site of protein synthesis
What are the characteristics of SER?
1) It does not have ribosomes attached
2) It is the major site of lipid and carbs synthesis
What is the function of SER?
It catalyzes the ff rxns in various organs of the body:
1) Liver
2) Testes
3) Intestinal cells
4) Skeletal and cardiac muscle
What are the rxns (or actions) done by the liver (w/c is catalyzed by the SER)?
1) Lipid and chole metabolism
2) Breakdown of glycogen and along w/ the kidneys
3) Detoxify drugs
What is the rxn (or action) done by the testes (w/c is catalyzed by the SER)?
Synthesis of steroid-based hormones
What are the rxns (or actions) done by the intestinal cells (w/c is catalyzed by the SER)?
1) Absorption, 2) synthesis, and 3) transport of fats
What are the rxns (or actions) done by the skeletal and cardiac muscle (w/c is catalyzed by the SER)?
1) Storage and 2) release of calcium
What is golgi apparatus and what are its functions?
It is a series of closely packed membranous sacs that collect, package, and distribute proteins and lipids produced by the ER
What are secretory vesicles and what are its functions?
These are small, membrane-bound sacs that transport mat from the golgi apparatus to the exterior of the cell
What are the functions (or mechanism) of the golgi apparatus?
1) Some proteins are produced at ribosomes on the surface of the RER and are transferred into the cisterna as they are produced
2) The proteins are surrounded by a vesicle that forms from the membrane of the ER
3) This transport vesicle moves from the ER to the golgi apparatus, fuses w/ its membrane, and releases the proteins into its cisterna
4) The golgi apparatus concentrates and in some cases, modifies the proteins into glycoproteins or lipoproteins
5) The proteins are packaged into vesicles that form from the membrane of the golgi apparatus
6) Some vesicles, such as lysosomes, contain enzymes that are used within the cell
7) Secretory vesicles carry proteins to the plasma membrane, where the proteins are secreted from the cell by exocytosis
8) Some vesicles contain proteins that become part of the plasma membrane
What are lysosomes?
These are spherical membranous bags containing digestive enzymes
What are the functions of lysosomes?
1) Digest ingested bacteria, viruses, and toxins
2) Degrade nonfunctional organelles
3) Breakdown glycogen and release thyroid hormone
4) Breakdown non-useful tissue
5) Breakdown bone to release Ca2+
Where are secretory lysosomes found?
These are found in WBCs, immune cells, and melanocytes
What are peroxisomes?
These are membranous sacs containing oxidases and catalases
What are the functions of peroxisomes?
1) Breakdown fatty acids, AAs, and H2O2
2) Detoxify harmful or toxic substances
3) Neutralize dangerous free radicals
What are free radicals?
These are highly reactive chemicals w/ unpaired electrons
Provide an ex of free radicals
O2^-
What are the characteristics of mitochondria?
1) They are the major sites of the production of ATP via aerobic cellular respiration
2) They have a smooth outer membrane and an inner membrane that is infolded to produce cristae
3) They contain their own DNA
4) They can produce some of their proteins
5) They can replicate independently of the cell
What are the characteristics of centrioles?
1) They are cylindrical organelles
2) They are located in the centrosome
3) Has a pinwheel array of 9 triplets of microtubules
What are the characteristics of centrosome?
1) It is a specialized zone of the cytoplasm
2) It is the site of microtubule formation
Microtubules are called as what?
Spindle fibers
What is the characteristic of microtubules?
They extend out in all directions from the centrosome
What is the characteristic of spindle fibers?
They are involved in the separation of chromosomes during cell division
What is the purpose of centrioles?
They form the bases of cilia and flagella
What is the function of cilia?
To move substances over the surface of cells
What is the characteristic of flagella (in comparison w/ cilia)?
Flagella are much longer than cilia
What is the function of flagella?
They propel sperm cells
What are the functions of microvilli?
1) Increase the surface area of cell
2) Aid in absorption and secretion
