Flashcards in Cells Deck (66):
1. Cells are the smallest structural and functional units of life.
2. All cells come from other cells
3. All living things are composed of one or more cells.
What does the cytoplasm contain?
What is Cytosol?
Liquid inside the cell organelles are suspended in.
What is an Organelle?
A small cellular structure that preform specific metabolic functions for the cell as a whole
What is the structure of the Plasma Membrane?
The plasma membrane is composed of a semipermeable phospholipid bilayer. The medial and lateral edges of border are hydrophilic while the center is hydrophobic. Membrane also contains proteins and cholesterol.
What is the function of the mitochondria?
To produce ATP
Which organs are likely to have more peroxisomes?
Liver and Kidney cells are likely to have more peroxisomes due to the fact that these organs specialize in detoxification.
Which organs have more Mitochondria?
The Kidney and Liver because these organs are very active. Unchallenged lymphocytes have a minimal amount.
Which Organelle is the major site of ATP synthesis?
What are the three organelles involves in protein synthesis and how do these organelles interact in that process?
Ribosomes make protein, the rough ER provides a site for ribosome attachment. RER cisterns package proteins made on ribosomes in vesicles for transport to Golgi apparatus. The Golgi app. Modifies and packages the proteins for extra cellular and intercellular use.
Compare the functions of lysosomes and peroxisomes.
Lysosomes use enzymes to to digest foreign substances engulfed by cell, damaged and nonuseful organelles, to prevent build up of cellular debris. Peroxisomes detoxify harmful chems. And neutralize free radicles.
What is the function of the plasma membrane?
Serves as an external cell barrier, and acts in transport of substance into or out of the cell. Externally facing proteins act as receptors , transport proteins, and in cell to cell recognition.
What is the structure of the Mitochondria?
Rodlike, double-membrane structures; inner membrane folded into projections called cristae.
Structure and function of ribosomes
Dense particles consisting of 2 subunits, each composed of ribosomal RNA and protein. Free or attached to endoplasmic reticulum. They serve as the sites for protein synthesis
Structure and function of rough ER.
Membranous system enclosing a cavity, the cistern , and coiling through the cytoplasm. Externally studded with ribosomes. Sugar groups are attached to proteins within cisterns. Proteins are bound in vesicles for transport to the Golgi apparatus and other sites. external face synthesizes phospholipids
Peroxisomes structure and function
Membranous sacs of catalase and oxidase enzymes. The enzymes detoxify a number of toxic substances. The most important enzyme, catalase, breaks down hydrogen peroxide
What is the structure and fiction of the Golgi apparatus?
A stack of flattened membranes and associated vesicles close to the nucleus. Packages, modifies, and segregates proteins for excretion from the cell, inclusion in lysosomes, and incorporation into the plasma membrane.
Structure and function of smooth ER
Membranous system of sacs and tubules; free of ribosomes. Site of lipid and steroid (cholesterol) synthesis, lipid metabolism, and drug detoxification
What is the structure and function of lysosomes?
Membranous sacs containing acid hydrolases. Sites of intraclular digestion (old/damaged organelles and bacteria)
What is the structure and function of micro tubules?
Cylindrical structures made of Tubulin proteins. Supports cell and gives it shape. Involved in intracellular and cellular movements. Forms centrioles and cilia and flagella, if present.
Structure and function of micro filaments?
Fine filaments composed of the protein actin. Involved in muscle contraction and other types on intracellular movement, help from the cell's cytoskeleton.
Structure and function of intermediate filaments
Protein fibers; composition varies. The stable cytoskeleton elements resist mechanical forces acting on the cell
Structure and function of centrioles?
Paired cylindrical bodies, each composed of nine triplets of microtubules. Part of centrosome, organize a microtubule network during mitosis. To form the spindle and astersfrm the bases of the cilia and flagella.
What is an inclusion?
Varied; includes stored nutrients such as lipid droplets and glycogen granules, protein, crystals, pigment granules
Structure and function of nucleus?
Largest organelle. Surrounded by the nuclear envelop; contains fluid nucleoplasm, nucleoli and
Chromatin. It is he control center of the cell; responsible for transmitting genetic info. And providing the instructions for protein synthesis.
Structure and function of nucleolus?
Dense spherical (non-membrane bounded) bodies, composed of ribosomal RNA and proteins. Site of ribosome synthesis.
Support and help generate movement.
What is the cell cycle?
The series of changes a cell goes through from the time it is formed until it reproduces.
What is Interphase, what happens in interphase?
Interphase is the period from cell formation to cell division. Cell is not dividing, it carries out normal metabolic activity.
What is Mitosis, what happens during mitosis?
Mitosis is the series of events that parcels out the replicated DNA of the mother cell to two daughter cells.
What are the 4 phases of mitosis?
What is Cytokinesis?
Cytokinesis means division of the cytoplasm . It begins during the late anaphase and is completed after mitosis ends.
Cell only carries out normal metabolic activity and grows. Interphase is not part of mitosis.
- DNA is in the form of chromatin
-nuclear envelope and nucleoli are intact and visable.
What are the three distinct periods of interphase?
G1: the centrioles begin replicating
S: DNA is replicated
G2: final prep for mitosis are completed, centrioles finish replicating.
What happens during early prophase?
- chromatin condenses, forming bar like chromosomes.
- each duplicated chromosome consists of 2 identical threads, called sister chromatids, held together at the centromere. Once separated each will be a new chromosome.
- as chromosomes appear nucleoli disappear, and the two centrosomes separate from one another.
- centrosomes act as focal points for growth of a micro tubule assembly called the Mitotic Spindle. As the microtubules lengthen , they propel the centrosomes toward opposite ends of the cell.
-microtubule arrays called asters extend from centrosomes matrix.
What happens during late prophase?
- Nuclear envelope breaks up allowing spindle to interact with chromosomes.
- Some of the growing spindle microtubules attach to kinetochores (kinetokors) special protein structures at each chromosome'a centromere. Such microtubules are called kinetochore microtubules.
- The remaining spindle microtubules (not attached to chromosomes) are called polar microtubules . The microtubules slide past each other, forcing the poles apart.
- The kinetochore microtubules pull on each chromosome from both poles in a tug-of-war that ultimately draws the chromosomes to the equator of the cell.
What happens during metaphase?
- the 2 centrosomes are at opposite poles of the cell
- the chromosomes cluster at the midline of the cell, with their centromeres precisely aligned at the equator of the spindle. This imaginary plane midway between the poles is called the metaphase plate.
- Enzymes act to separate the chromatids from each other
What happens during anaphase?
- shortest phase of mitosis, anaphase begins abruptly as the centromeres of each chromosomes split simultaneously. Each chromatid becomes a chromosome in its own right.
- the kinetochore microtubules , moved along by motor proteins in the kinetochore, gradually pull each chromosome toward the pole it faces.
- at the same time the polar microtubules slide past each other, lengthen , and push the 2 poles of the cell apart.
- the moving chromosomes look V shaped. The centromeres lead the way. And the chromosomal "arms" dangle behind them.
- moving and separating Christine's is helped by the fact that the chromosomes are short, compact bodies. Diffuse threads of chromatin would trail, tangle and break, resulting in imprecise "parcelling out" to the daughter cells.
What happens during telophase?
- telophase begins after chromosomal movement has stoped. This final stage is like prophase in reverse.
- the identical sets of of chromosomes at the opposite poles of the cell uncoil and resume their threadlike chromatin form.
- a new nuclear envelope forms around each chromatin mas, nucleoli reappear with in the nuclei, and the spindle breaks down and disappears.
- mitosis is now ended. The cell, for just a brief period, binucleate (has 2 nuclei) and each new nucleus is identical to the original mother cell nucleus.
What happens during cytokinesis?
Cytokinesis begins during late anaphase and continues through and beyond telophase. A contractile ring of actin micro filaments forms the cleavage furrow and pinches the cell apart.
The smallest unit of life capable of life by itself.
The major types of lipid found in the plasma membrane are...
Membrane junctions that allow nutrients or ions to flow from cell to cell are...
The endocytotic process in which a sampling of particulate matter is engulfed and bought into a cell is called....
Which is not true of centrioles?
A) they start to duplicate in g1
B) they lie in the centrosome
C) they are made of microtubules
D) they are membrane-walled barrels laying parallel to each other
The nuclear substance composed of histone proteins and DNA is ...
B) the nucleolus
C) nuclear sap, or nucleoplasm
D) nuclear pores
Mutations may be caused by...
B) certain chemicals
C) radiation form ionizing radioisotopes
D) all of these
The phase of mitosis during which centrioles reach the poles and chromosomes attach to the spindle is...
Final preparations for cell division are made in the life cycle sub phase called..
Which organelle is responsible is responsible for a newborn having distinctive toes and fingers instead of webbed digits?
Explain why mitosis can be thought of as cellular immortality...
Cells lining the trachea have whiplike motile extensions on their fee surfaces. What are these extensions, what is their source and what is their function?
Name the 3 phases of interphase and describe an activity unique to each phase.
Cell division typically yields 2 daughter cells, each with one nucleus. How is the occasional binucleate condition of liver cells explained?
The normal function of one tumor suppressor gene is to prevent cells with damaged chromosomes and DNA from "progressing from G1 to S", where as another tumor suppressor gene prevents "passage from G2 to M". When these tumor suppressor genes fail to work, cancer can result. Explain what the phrases in quotation mean.
In their anatomy lab, many students are exposed to the chemical preservatives phenol, formaldehyde, and alcohol. Our cells break down these toxins ver effectively. What cellular organelle is responsible for this?
Dunedin is missing from the cilia and flagella of individuals with a specific inherited disorder. These individuals has severe respiratory problems and if males are sterile. What is the structural connection between these 2 symptoms?
Explain why alcoholics are likely to have much more smooth ER than teetotalers...
Without growing: abnormalities in cell structure and loss of differentiation
Abnormal: a change in cell sizes, shape, or arrangement due to chronic irritation or inflammation
Growth of an organ or tissue due to an increase in the size of cells.
Hollow microscopic sacs formed of phospholipids that can be filled with a variety of drugs. Serve as multipurpose vehicles for drugs, genetic material, and cosmetics
A change in DNA base sequence that may lead to incorporation of incorrect amino acids in particular positions in the resulting protein; the affected protein may remain unimpaired or May function abnormally or not at all, leading to disease.
Death+process: death of a cell or group of cells due to injury or disease . Acute injury causes the cells to swell and burst, and induces the inflammatory response. Uncontrolled death as compared to apoptosis.
What is a centromere?
The point or region on a chromosome where the spindle attaches.