Chapter 3 PPT Flashcards
The cell is
the basic unit of structure and function in the body
cells are measured in
micrometers
cells that have developed specialized characteristics are said to be
differentiated
What are the three major parts of a cell?
Nucleus
Cytoplasm
Cell Membrane
Cytoplasm consists of
organelles, with specific functions, suspended in a liquid called cytosol
What does the cell membrane do?
It is the outer boundary of the cell and maintains integrity of the cell.
Cell Membrane regulates
entry and exit of substances, meaning it is selectively permeable.
What is signal transfuction?
Permits cells to receive and respond to messages
What does the cell membrane consist of?
Mainly of lipids and proteins, with some carbohydrates
Cell membrane framework is a
phospholipid bilayer
What forms the surface of the phosopholipid bilayer?
Water-soluble (hydrophilic) heads
What forms the interior of the phosopholipid bilayer?
Water-insoluble (hydrophobic) tails
Bilayer is permeable to
lipid-soluble substances
bilayer is impermeable to
water-soluble substances
What does Cholesterol do with the cell membrane?
Stabilizes membrane, and helps keep it impermeable to water-soluble susbtances
What do Carbohydrates do with the cell membrane?
Cel recognition and interaction, cell markers
What do Mutations in Na+ Channels cause?
Inability to feel pain or extreme pain conditions
What do mutations in K+ channels cause?
Can disrupt electrical activity of the heart and disturb heart rhythm, and/or impair hearing
What do abnormal Cl- channels cause?
Cystic Fibrosis: Production of thick mucus which causes difficulty breathing, clogged pancreas, salty sweat
What do CAMs do?
Guide cells on the move
What do Selectins do?
Coat white blood cells and anchor them by providing friction
What do Integrins do?
Direct white blood cells through capillary walls toward infection sites .Integrins guide embryonic cells toward maternal cells to form placenta and establish connectiosn between nerve cells
What does cytoplasm consist of?
Networks of membranes and organelles suspended in cytosol.
What is cytosol?
Fluid portion of the cytoplasm
What are organelles?
Tiny soldi structures with specific functions in the cells
What are ribosomes?
Composed of protein and RNA. Free in cytoplasm or on RER
Provides structural support and enzyme activity to link amino acids in protein synthesis
What is the Endoplasmic Reticulum
Membrane-Bound Sacs, Canals, Vesicles
Tubular Transport System
ER- Rough ER contains
ribosomes, conducts protein synthesis
ER- Smooth ER
does not have ribosomes, conducts lipid synthesis
What are vesicles?
membranous sacs
Store or transport substances
What is the Golgi apparatus?
Sacs of flattened membranous sacs
Refines, packages, and delivers proteins made on the RER
Structure of Mitochondria?
Membrane-bound, fluid-filled sacs
Mitochondria houses
chemical reactions that extract energy from nutrients (cellular respiration, which produces ATP)
Lysosomes Structure
Small membranous sacs
Lysosomes description?
Contains enzymes that digest proteins, carbohydrates, nucleic acids, bacteria, debris, worn out cell parts
Lysosomes also known as
“garbage disposals” of cell
Peroxisomes structure?
Membranous sacs similar to lysosomes
Peroxisomes Descrption?
Contain enzymes that digest lipids, alcohol, hydrogen peroxide
What are microfilaments, microtubulues, and intermediate filaments?
Thread-like structures in cytoplasm. Create the cytoskeleton
What are microfilaments?
Tiny rods of actin; provide cellular movement such as muscle contractions.
Larger tubes of tubulin, rigidity maintains cell shape, make up cilia, flagella, and centrioles. And helps move organelles.
What are intermediate filaments?
Composed of several proteins. A cytoskeletal structure. Supports nuclear envelope
What is a centrosome?
“Central Body” consisting of two centrioles
Where is the centrosome located at?
in cytoplasm, near nucleus
Centrosome structure?
Cylindrical, composed of microtubulues
Centrosome Function?
Produce spindle fibers during cell division, which distribute chromosomes to forming daughter cells
Cilia are
motile extensions of cell membrane
cilia consist of
microtubulues in cylindrical pattern
cilia form
a “fringe” on surface of certain epithelial cells
cilia are shorter
than flagella, but very abundant when present
cilia propel
mucus in respiratory tract, propel egg toward uterus
flagella are another type of
motile extension from cell membrane
flagella are
similar in structure to cilia, but much longer
flagellum causes
the entire cell to move
tail of a sperm cell is
the only flagellum in a human cell
What is Melas?
Mutant gene in DNA of mitochondria
How does Melas affect a person?
Person cannot extract maximum energy from nutritents
What is Krabbe Disease?
Caused by inability to produce one lysosomal enzyme
How does Krabbes Disease affect a person?
Person cannot produce myelin for nerve cells, which leads to severe damage to the nervous system
What is ADL?
Caused by lack of a protein in membrane of peroxisomes
How does ADL affect a person?
Fatty acid buildup destroys myelin sheath of nerve cells. Nerve cells cannot transmit nerve impulses fast enough
What is the nuclear envelope?
Porous double layered membrane that separates nucleoplasm from cytoplasm. Nuclear pores allows passage of certain substances
What is a nucleolus?
Dense body of RNa and Protein. Site of ribosome production
What is a chromatin?
COnsists of cell’s chromsomes, each containing DNA wound around proteins. Stores information for protein synthesis
What are the Passive Processes?
Diffusion, Osmosis, Facilitated Diffusion , and Filtration
What are the Active Processes?
Active Transport
Endocytosis
Exocytosis
Transcytosis
What is Diffusionn?
Movement of atoms, molecules, or ions from region of higher concentration to region or lower concentration
Diffusion occurs
due to constant motion of atoms, molecules, and ions
Diffusion, only substances
that the cell membrane is permeable to. Oxygen, CO2, and other lipid soluble substances
What kind of process is diffusion?
Passive, no ATP required
Example of Diffusion?
A dissolving sugar cube
What is Facilitated Diffusion?
Diffusion across the cell membrane through ion channels or transporters
Facilitated Diffusion contains what water-soluble substances?
Na+, K+, Cl-, Glucose, Amino Acids
What kind of process is Facilitated Diffusion?
PAssive Process, no ATP required
What is Osmosis?
movement of water across a selectively permeable membrane from a region of higher water concentration to a region of lower water concentration
osmosis- water moves into
a region containing higher impermeant solute concentration
what kind of process is osmosis?
Passive process, no ATP required
what is osmotic pressure?
ability of osmosis to generate enough pressure to lift a volume of water.
Osmotic pressures inceases as
the concentration of impermeant solute increases
What is a isotonic solution?
Same osmotic pressure. Cells in an isotonic solution have no neet gain or loss of water
what is a hypertonic solution?
higher osmotic pressure.
cells in a hypertonic solution lose water
what is a hypotonic solution?
lower osmotic pressure
cells in a hypotonic solution gain water
What is filtration?
process that forces molecules through membranes by exerting pressure
What is filtration used for?
used to separate solids from water, or small particles from large ones
example of filtration?
when blood plasma leaves capillaries, water and small solutes are filtered, but large plasma proteins are not
what type of process is filtration?
passive process, requires no ATP
what is active transport?
movement of substances across a membrane from region of lower concentration to region of higher concentration against a concentration gradient
active transport uses
carrier molecules in cell membrane
what kind of process is active transport
active process, requires ATP
examples of active transport?
sugars, amino acids, Ca+ H+ Na/K Pump
what is endocytosis?
movement of a substance into the cell inside a vesicle
Three types of endocytosis?
Pinocytosis
Phagocytosis
Receptor-Mediated Endocytosis
what is pinocytosis?
membrane engulfs droplets of liquid
what is phagocytosis?
membrane engulfs solid particles
what is receptor-mediated endocytosis?
membrane engulfs specific substances, which have bound to receptor proteins on the membrane
what is exocytosis?
release of substances/particles from cell
Exocytosis - vesicles containing particles..
fuse with cell membrane and release contents
example of exocytosis?
release of neurotransmitter from nerve cells
what does transcytosis involve?
involves receptor-mediated endocytosis followed by exocytosis
transcytosis quickly..
transports substances from one end of cell to the other
transcytosis moves
substances across barriers form by tightly connected cells
example of transcytosis?
transport of hiv across lining of anus or vagina
What is a cell cycle?
series of changes a cell undergoes from the time it forms until the time it divides
stages of cell cycle?
Inteprhase
Mitosis
Cytokinesis
Interphase is a
very active period in cell cycle where cell grows and maintains normal functions
Interphase - cell
replicates DNA to prepare for mitosis
Interphase - cell synthesizes
organelles, membranes, and biochemicals to prepare for cytokinesis
Phases of Interphase?
S Phase
G1 and G2 Phases
What is S Phase?
DNa is replicated during this
What is G1 and G2 Phase?
Structures other thana DNa are replicated and cell grows during this.
Mitosis produces
two daughter cells from an original somatic cell
what is mitosis?
division of the nucleus
what is cytokinesis?
division of the cytoplasm
Phases of Mitosis?
Prophase
Metaphase
Anaphase
Telophase
What is Prophase
Chromatin condenses to form chromosomes, centrioles move to opposite sides of cytoplasm, nuclear envelope and nucleolus disperse
what is metaphase
spindle fibers from centrioles attach to chromsomes and align them midway between centrioles
what is anaphase?
chromosomes separate and move in opposite directions toward centrioles as the spindle fibers shorten
what is telophase?
chromosomes return to chromatin structure, nuclear envelope forms around each chromosome set, and nucleoli became visible
What is cytokinesis?
cytoplasmic division
when does cytokinesis begin?
during anaphase
cytokinesis continues through
telophase
what happens during cytokinesis?
contractile ring of actin filaments pinches cytoplasm in half.
after cytokinesis, newly formed cells will
have identical DNA, may have slightly different size and number of organelles
SKin cells, intestinal cells, and blood -forming cells with divide
often and continually
neurons divide
a specific number of times, and then cease
chromosome tipis (telomeres) that shorten with each mitosis provide
a miotic clock
What is contact inhibition?
healthy cells stop dividing when they become crowded. Tumors can result from a loss of control over the frequency of mitosis
what are 2 types of tumors?
benign and malignant
what is a benign tumor?
remains in local area
what is a malignant tumor?
invasive, cancerous, can spread or metastasize
two major types of genes that cause cancer?
oncogenes
tumor suppressor genes
what are oncogenes?
abnormal forms of genes that control cell cycle but are overexpressed
what are tumor suppressor genes?
normally limit mitosis, but if inactivated/removed, cannot regulate mitosis
what is differentiaition?
process of specialization of cells
stem cells can divide to
form two new stem cells, called self-renewal
stem cells can also divide to
form a stem cell and a progenitor cell
stem cells can differentiate as
any of many cell types
what is a progenitor cell?
partially specialized stem cell, daughter of stem cell
progenitor cell can divide to
become any of a restricted number of cells, called a “committed cell”
what is totipotent?
daughter cells that can specialize to become any cell type?
totoipotent examples?
fertilized egg, cells of early embryo
what is pluripotent?
daughter cells that can become a limit number of cell types
examples of pluripotent?
stem cells of later development, progenitor cells
Example of differentiation
a fertilized egg has the ability to produce any type of human cell, while partially differentiate dcells can only produce some types or a sngle type of cell
stem and progenitor cells are required for
growth and healing
what is regenerative medicine?
field that uses bodys ability to generate new cells to treat diseases and injuries; includes stem cell technology
sources of stem cells for research, treating diease/injuries
donor stem cells
stem cells from patients
where do donor stem cells come from?
such as umbilical cord cells
where do stem cells from patients come from?
either form natural site, such as bone marrow, or reprogrammed differentiated cells grown in cell culture
what is apoptosis?
programmed cell death that is a normal part of development
apoptosis removes
webbing between fetal fingers and toes
apoptosis- protective
pells away damaged skin after a sunburn
what is necrosis
cell death from damage, not a normal process
