Cell structure Chp3 Flashcards
Cell
Is the structural & functional unit of all living matter
Cell is encased by a ________
Cell membrane
One of Cell membranes chief functions
Is the selection of substances allowed to enter or leave the cell. (Permeable/Semipermeable)
What makes up a cell membrane
Phospholipids & protein & small amount of carbohydrates.
Substances move across the semipermeable membrane in ___ ways
Two
First way substances move across the semipermeable membrane
Dissolving in the lipid portion of the membrane, as do oxygen & carbon dioxide.
2nd way substances move across the semipermeable membrane?
Substances can also cross the membrane by flowing through the pores.
Ex- Water & chloride cannot penetrate lipid membrane & must use pores.
-These are also called water-soluble-substances
Drugs are classified as _____ (fat)soluble or _____ soluble
- )Lipid
2. )Water
Cell is divided into two compartments
The nucleus & cytoplasm
Nucleus
Control center of the cell
Most adults cells have only ___ nucleus
1
Mature Red Blood Cells have ?
No Nucleus
Surrounding the nucleus is a ?
Double layered nuclear membrane
The nucleus is filled with a fluid substance called?
Nucleoplasm.
Within the nucleoplasm there are two other structures, what are they called?
Nucleolus & chromatin
Chromatic. Is composed mainly of strands of what?
DNA (Deoxyribonucleic Acid)- Which are the carriers of genetic code
Chromatin in non-dividing cells
Chromatin in Dividing cells
- ) Appears as a tangled array of fine filaments
2. )chromatin strands coil tightly,forming DNA-containing structures called chromosomes.
Cytoplasm contains the
Cytosol & organelles
Organelles (little organs)
Dispersed throughout the cytoplasm; each organelle has a specific role
What produces most of the energy in the body ?
Mitochondria
Mitochondria is referred to as the _____________ of cell
Power plants
Fixed ribosomes
Largely concerned with the synthesis of exportable protein——that is,protein secreted by the cell for use somewhere else in the body.
Ribosomes
Cytoplasmic organelles involved in protein synthesis.
Fixed Ribosomes
protein secreted by the cell for use elsewhere in the body
Free ribosomes
- Float freely within cytoplasm
- Generally synthesize proteins that are used within the cell
Endoplasmic reticulum
Is a network of membranes within the cytoplasm.
-long folded membranes form channels through which substances, especially newly synthesized protein,move.
RER
- )Rough endoplasmic reticulum-rough sandpaper like appearance.
- is primarily concerned with protein synthesis
SER
The ER (Endoplasmic reticulum) that does not contain ribosomes on its surface appears smooth; is smooth endoplasmic reticulum. -primarily involved in the synthesis of lipids, steroids,glycerides, and glycogen in skeletal muscle & liver cells
Golgi apparatus
Series of flattened membranous sacs.
Lysosomes
Membranous sacs containing powerful enzymes.
-Lysosomal enzymes break down intercellular waste & debris, including damaged organelles, thus helping “clean house.”
Cytoskeleton
Composed of threadlike structures called microfilaments & microtubules.
- helps maintain the shape of the cell & assist the cell in various forms of cellular movement.
Cellular movement is particularly evident in ________, which contain large numbers of _____________.
- ) Muscle Cells
2. )Microfilaments
____________ are the primary component of the cytoskeleton.
Microtubules
Microtubules also play a key role in cell division by?
Forming the spindle apparatus that helps distribute the chromosomes to opposite ends of the dividing cell.
Centrioles
Paired,rod-shaped, & short micro-tubular structures that form the spindle apparatus in a dividing cell.
Cells that have no _______ are incapable of cell division
Centrioles
Ex- neurons, mature RBCs, skeletal muscle cells, & cardiac muscle cells
The cytoplasm surrounding the centrioles is called the ?
-Centrosome
Microtubules of the cytoskeleton begin at the _______ & spread throughout the _________.
- ) Centrosome
2. )Cytoplasm
Microvilli
Membrane forms Accordion-like folds
- For cells that are particularly involved w/ the movement of large amounts of water & its dissolved solutes.
Cilia
Short, hairlike projections on the outer surface of the cell membrane.
- use wavelike motions to move substances across the surface of the cell.
Flagella (whiplike, Hairlike)
Similar to Cilia, but flagella are thicker, longer, & fewer in number; they help move the cell.
Ex-tail of the sperm is flagella
Tonicity
Is the ability of a solution to affect the volume & pressure within a cell.
Three terms are used to illustrate tonicity:
Isotonic,hypotonic, & hypertonic
Isotonic solution
No net movement of water occurs; cell neither gains nor loses water
Hypotonic solution
Too much water in cell; leads to burst or lyse of cell.
Hypertonic solutions
If an RBC (Red Blood Cell) is placed within a very concentrated solution, water diffuses out of the RBC into the bathing solution, causing an RBC to shrink
- the salt solution is referred to as a hypertonic solution.
If cell gains water
RBC or cell bursts
If the RBC loses water
The cells shrink
Isotonic solutions do not cause cells to _____ or ______
Swell or shrink
Normal saline
-also a commonly used isotonic solution
0.9%NaCl ( Sodium Chloride )
5%D/W
5% dextrose/glucose in water
K+
Potassium
Filtration
Pressure pushes substances across the membrane.
- water & dissolved substances cross the membrane in response to differences in pressures.
Where does filtration occur in the body ?
The movement of fluid across the capillary wall can be compared with the movement of water in the syringes with holes in its side
Capillary
Is a tiny vessel that contains blood.
The capillary wall is composed of a ____ _____ of cells with many little pores
Thin layer
Cell division is necessary for the body’s ______,______,&_______
Growth,repair,& reproduction
Two type of cell division
Mitosis & meiosis
Meiosis only occurs in ___ cells.
Sex
Mitosis
Is the splitting of one mother cell into two identical “daughter cells”
-involved in bodily grown & repair
Copy of genetic info stored within chromosomes is passed to the two daughter cells.
Cell cycle
Is the sequence of events that the cell goes through from one mitotic division to the next.
Cell cycle is divided into two major phases;
Interphase & mitosis
During interphase;
The cell carries on with its normal functions & get ready for mitosis through growth & DNA replication.
Interphase is divided into 3 phases
-First gap phase (G1)
-phase (S)
Second Gap phase(G2)
First gap phase (G1)
Cell carries on normal activities & begins to make DNA and other substances necessary for cell division
Phase S
The cell duplicates it’s chromosomes, thereby making enough DNA for two identical cells.
Second gap phase (G2)
This phase is the final prep phase for cell division (Mitosis); includes synthesis of enzymes & other proteins needed for mitosis
At the end of G2, the cells enters the _____ phase
Mitotic
During the Mitotic (M) phase
The cell divides into two cells with identical genetic information in their nuclei
Mitosis consists of four phases;
- Prophase
- Metaphase
- Anaphase
- Telophase
During prophase
- The chromosomes coil so tightly that they become visible under a light microscope.
- Each chromosomes pair is composed of two identical strands of DNA called chromatids
- Each chromatid is attached at a point called the centromere.
- at the same time, two pairs of centrioles move to opposite poles of the nucleus
- Late in prophase, the nuclear membrane disappears
Each chromatid is attached at point called the
Centromere
During metaphase
The chromatids are aligned in a narrow central zone; spindle fibers connect the chromatids & centrioles.
Anaphase begins
When the centromere splits & the chromatids are pulled to opposite poles. (Away) (end of anaphase)
During telophase
Each new cell reverts to the interphase state; the nuclear membrane reforms, the chromosomes uncoil & the chromatin strands reappear.
______ & ________ mark the end of mitosis
Telophase & cytokinesis
Cytokinesis is
The pinching of the cell membrane to split the cytoplasm into two distinct cells.
-begins in late anaphase.
What are two choices that two daughter cells have at end of mitosis?
Enter G1 & repeat the cycle (and divide again) or Ebro G0, which is dropping out of the cell cycle and resting.
Anticancer drugs are called
Cell cycle phase-specific
Some anticancer drugs can act at any phase of the cell cycle & are called
Cell cycle phase-nonspecific
Mitosis assured us that the division of one cell produces ____ _____ _____
Two identical cells
An embryo begins life as a
Single cell
Failure to differentiate is characteristic of ______ ______
Cancer cells.
Differentiation
Process whereby a cell becomes specialized
Stem cells
Relatively undifferentiated or unspecialized cells whose only function is the production of addition unspecialized cells.
Most cell growth is _____
Orderly
When cells become uncontrolled & disorganized too many cells are produced & results in a
Lump/tumor/swelling
Tumors can be classified as
Benign (non cancerous)
Malignant (cancerous)
Cancer means
“Crab”
- like a crab send out claw like extensions that invade surrounding tissue.
Cancers can also detach from the original tumor (primary site) & spread throughout the body (secondary site)
The spreading of cancer cells is referred to as
Metastasis
Programmed sequence of events that leads to a cells death
Apoptosis
Apoptosis helps rid the body of ___, _________,& _________ cells
Old, unnecessary, & unhealthy
Pap smear
Is a diagnostic procedure used to detect cancer
