Chapter 3 Flashcards
What is Cytology?
Study of Cellular Structure and Function
How many kinds of cells are there in the human body?
200
What is considered the nucleus’ largest organelle?
Cytoplasm
What are the parts of the Cytoplasm?
1) Cytoskeleton –> The Supportive Framework of fillaments and tubules
2) Organelles –> Diverse Structures performing tasks in the cell
3) Inclusions –> Accumulated cell products (e.g. lipids, pigaments and bacteria)
4) Cytosol –> Clear gel embedding the other components
Another name for the Cytosol is
Intracellular fluid (ICF)
The Extracellular Fluid (ECF) between the cells is referred to as ________?
Tissue Fluid
What is the Plasma Membrane?
1) Membrane at cell surface
2) Defines boundary of the cell
3) Governs interactions with other cells
4) Maintains chemical composition differences (between ECF and ICF)
5) 2 -layered lipid film with embedded proteins
What are Phospholipids?
Lipid in the Plasma Membrane which is highly fluid and is 75% of lipid molecules. They have Hydrophillic head (faces water on inside and outside of cell) and 2 Hydrophobic Fatty acid tails (Forms middle of Phospholipid bilayer away from water.
What is Cholesterol?
The lipid in the Plamsa Membrane which is 20% of lipid molecules. Affects membrane fluidity. If too much, inhibits proteins and molecules in membrane. If too little, Plasma Membrane Fragile.
What is the difference between Integral and peripheral proteins?
Inegral proteins penetrate the cell membrane and have glycoproteins (Proteins with carbohydrates attached). Peripheral proteins do not protrude into phospholipid; they are usually on intracellular face.
What are some functions of Membrane Proteins?
1) Receptors
2) Enzymes
3) Channel Proteins
4) Carriers
5) Cell identity markers
6) Cell Adhesion Molecules (CAM) –> Link cells to each other, link cells to extracellular material, bind tissues together, needed for sperm-egg binding, and immune cell binding
What is Glycocalyx?
- Fuzzy Carbohydrate coat covering cells
- Short sugar chain of glycolipids and glycoproteins.
- Function as cell-adhesion molectules, cushions plasma membrane, helps in ability to distinguish healthy cells, and determines human blood type and transfusion compatibility
What is Microvilli?
Extension of plasma membrane, serves primarily to increase surface area (Gives cell up to 40 times more surface area), well developed in taste buds and inner ear.
What are Cillia?
- Hair-like extensions
What are Motile Cilia?
- Less wide-spread
- Abundant in mucous membranes of respiratory tract (Moves mucus from lungs to throat)
- Abundant in Uterine Tubes (Move egg or embryo to uterus)
What are cell junctions?
Formed by proteins at cell surface, link cells together, attach them to extracellular material.
- Enable cells to grow/divide normally, resist stress, and communicate with each other
What are the 3 types of Cell Junctions?
1) Tight Junctions –> Completely encircles epithelial cell near upper end. Formed by fusion of fusion of plasma membrane of adjacent cells. Makes it difficult for substances to leak between cells (digestive juices from seeping between epithelial cells)
2) Desmosomes –> Hold cells together at specific point, not continuous, keep cells from pulling apart, enable tissues to resist mechanical stress, common in epidermis and cardiac muscle
3) gap junctions –> Formed by ring of proteins surrounding channel. Diffusion through channel
What are half desmosomes called?
hemidesmosomes –> anchor epithelial cell to basement membrane
What does it mean that the plasma membrane is selectively permeable?
- Allows some substatnces to pass
- Holds back others
- Multiple method of transport through cell’s surface
What is simple diffusion?
- Net movement of particles from high concentration to low concentration (i.e. down a concentration gradient)
- How O2 & Steroid Hormones enter a cell
- Does not require energy by cell
What is osmosis?
Net movement of H2O (from lower solute concentrations to higher)
- Plays key role in Homeostasis (e.g. cell volume, blood capilaries absorbing fluid)
What is facilitated diffusion?
- Carrier-mediated transport
- Movement of solute down concentration gradient
- Occurs with the aid of a carrier
- Does not require energy use by cell
- Transports solutes that could not get through membrane (Absorption of sugars from Digestive food)
What is active transport?
- Requires energy input
- Moves solute up its concentration gradient (from less to more)
- Ceases immediately if cell stops producing ATP
What is the Sodium-Potassium pump?
- Important active-transport process (Uses ATP, Large source of daily caloric needs)
- Na normally more concentrated in ECF
- K normally more concentrated in ICF
- Binds 3 Na and pumps OUT of cell. Binds 2 K and Pumps INTO the cell
What are the roles of the Na-K Pump?
- Controlling cell volume
- generating body heat
- Providing energy for other transport pumps
What is the difference between Endocytosis and Exocytosis?
Endocytosis brings matter INTO cell. Exocytosis exports material from cell
What are the 3 forms of endocytosis?
1) Phagocytosis –> cell-eating, has psedopods reaching out of cell
2) Pinocytosis –> “cell-drinking”; occurs in all human cells; contains droplets of ECF
3) Receptor-Mediated Endocytosis –> More selective,
What is the Cytoskeleton?
- Network of protein filaments and tubules in cytoplasm
- Structurally supports cell
- Determines shape and organizes content
- Transports substatnces within cell
- Contributes to cell movement
- connected to proteins in plasma membrane
What are organelles?
- Play important role in cell-survival
- Compartmentalized components of cell
What is the nucleus?
Largest organelle,
How many nuclei are in mature red blood cells?
0
What is the nuclear envelope?
2 paralel membranes surrounding nucleus
- perforated by nuclear pores (regulate traffic into and out of nucleus; bind 2 membrane together)
What are chromosomes?
- Threadlike bodies in cell
- Found in Nucleus
How man Chromosomes are found in the human body?
46
Chromosomes contain ______?
Chromatin
What is the Endoplamic Reticulum?
- System of interconnected channels called cistern
- Synthesizes steroid and other lipids
- Manufactures cell’s membrane
- Produces Phospolipids and plasma membrane proteins
- Produces proteins for secretion of lysosomes
What is the difference between the Smooth ER and Rough ER?
- Smooth ER have cisternae which lack ribosomes. It is abundant in cells that synthesize steroid hormones (testes and ovaries) and abundant in cells specializing in detoxification (liver cells)
- Rough ER has cisternae covered with ribosomes. it is continuous with outer membrane of nuclear envelope and is most abundant in cells making lots of proteins.
What are Ribosomes?
- Small granules of proteins and rRNA
- Produced in nucleus
- “READ” genetic messages from nucleus
- Assemble amino acids into proteins specified by code
-
What is the Golgi Complex?
- Small Cluster of Cisternae
- Synthesize Carbohydrates
- Complete protein and glycoprotein synthesis
What are lysosomes?
Package of enzymes enclosed in membrane
- Often oval or round
- Break down proteins, nucleic acids, and carbohydrates, phospolipds and other substances
- Digest and destroy microbes in White Blood Cells
- Digest worn out organelles
- Help carry out apoptosis (pre-arranged cell suicide in no longer needed cells)
What are Perixisomes?
- Resemble Lysosomes but contain different enzymes
- Abundant in liver and kidney cells
- Breakdown fatty acids into 2 carbon molecules
- Neutralize free radicals
- detoxify drugs
- kill bacteria
- produce hydrogen peroxide
What are Mitochondria?
- Specialized for ATP synthesis
- Surrounded by double membrane
What is the inner membrane of Mitochondria called?
Cristae –> bear enzymes that produce most ATP
What is Mitochondrial Matrix?
Space between the cristae
How are centrioles arranged?
9 groups of 3 each
What are the steps of protein synthesis?
1) Transcription
2) Translation –> mRNA translated into amino acids
How many codons are there in the genetic code?
64
How many amino acids are composing protein?
20
What are Codons?
3 base segments of mRNA
What are the 4 steps of Mitosis?
Prophase –> Coiling of chromosomes into dense rods, disintegration of nuclear envelope,
Metaphase –> Chromosomes alligned at the equator, awaiting signal to split in 2 at centromere
Anaphase –> Centromere cleaved in 2 by enzyme ; daughter chromosomes
Telephase –> Clustering of chromatics on each side of the cell; new nuclear envelope; chromatids begin to uncoil
What is cytokinesis?
Division of the cytoplasm, overlaps with telophase
