Cell Flashcards
In 1665, ____ used a microscope to examine a thin slice of cork
Robert Hooke
In 1673, _____ was first to view living organisms
Leeuwenhoek
In 1838, a German botanist named ____ concluded that all plants were made of cells
Matthias Schleiden
In 1839, a German zoologist named _____ concluded that all animals were made of cells
Theodore Schwann
___&___ are the cofounders of the cell theory
Theodore Schwann
Matthias Schleiden
In 1855, a German medical doctor named ____ observed cell dividing under the microscope and reasoned that all cells come from pre-existing cells by cell division
Rudolph Virchow
The three postulates of the cell theory are?
All living things are made of cells
Cells are the basic unit of structure and function in an organism
Cells come from pre-existing cells through cell division
The two types of cells are?
Prokaryotes
Eukaryotes
Cells that lack a nucleus or membrane bound organelles are called?
Prokaryotes
Four features of prokaryotes are?
Single circular chromosome
Nucleoid region
Surrounded by cell membrane and cell wall
Contain ribosomes
The two types of cells are?
Prokaryotes
Eukaryotes
Cells that lack a nucleus or membrane bound organelles are called?
Prokaryotes
Four features of prokaryotes are?
Single circular chromosome
Nucleoid region
Surrounded by cell membrane and cell wall
Contain ribosomes
Cells that have a nucleus or membrane bound organelles are called?
Eukaryotes
Example of prokaryotes are?
Bacteria
Examples of Eukaryotes are?
Protists
Fungi
Plants
Animals
Three main features of eukaryotes are?
Nucleus
Cell membrane
Cytoplasm with membrane bound organelles
Two main types of Eukaryotic cell are?
Plant cell
Animal cell
Four features of organelles are?
Microscopic
Perform various cell functions
May or not be membrane-bound
Found in the cytoplasm
Some examples of cell organelles are?
Cell or plasma membrane Lysosome Ribosome Endoplasmic reticulum Nucleus Golgi bodies Centrioles Mitochondria
The cell/plasma membrane is composed of____&____
Double layer of phospholipids
Proteins
Two functions of cell membrane are?
Protection
Selective permeability
Allow cell recognition
Anchoring sites for cytoskeleton filaments
Phospholipids heads contain glycerol & phosphate and are _____
Hydrophilic
Phospholipids tails are made of fatty acids and are ____
Hydrophobic
Phospholipids make up a ____ where tails point inward toward each other
Lipid Bilayer
Phospholipids can move ___ to allow small molecules(CO2, O2 & H2O)
Laterally
____ help move large molecules or aid in cell recognition
Cell membrane proteins
Two types of cell membrane proteins are?
Peripheral
Integral
____are attached on the inner or outer surface of the cell membrane
Peripheral proteins
___ are embedded completely through the memebrane
Integral proteins
Jelly-like substance enclosed by cell membrane is called?
Cytoplasm
Two functions of cytoplasm are?
Provides a medium for chemical reactions to take place
Contains organelles
The cell organelle bounded by a nuclear envelope/membrane with pores is called?
Nucleus (usually the largest organelle)
Two function of the nucleus are ?
Control and coordinate all the activities of the cell
Contains DNA in chromosomes
A double membrane surrounding the nucleus is called?
Nuclear envelope/memebrane (contains nuclear pores for materials to enter and leave the nucleus)
DNA appears as _____ in non-dividing cells
Chromatin
DNA is condensed and wrapped around proteins to form?
Chromosomes
____ is the hereditary material of the cell
DNA
The organelle that makes ribosomes inside the nucleus is called?
Nucleolus(disappears when cell divides)
The functions of the cytoskeleton are?
It helps cell maintain cell shape
It helps move organelles around
Cytoskeleton a is made up of____, ____&____
Proteins
Microfilaments(threadlike, made of actin)
Microtubules (tubelike, made of tubulin)
The organelle found in animal cells only is?
Centrioles
The function of centrioles is?
To form mitotic spindle to pull chromosome pairs apart to opposite ends of cells
The site of cellular respiration in the cell is?
Mitochondria
Two features of mitochondria are?
Cristae(folded inner membrane)
Matrix(interior)
Mitochondria are inherited from your ____
Mother(egg cell)
Network of hollow membrane tubules connected to nuclear envelope & cell membrane is called?
Endoplasmic reticulum
Two functions of endoplasmic reticulum are?
Synthesis of cell products
Transport
Two kinds of Endoplasmic reticulum are?
Rough
Smooth
Rough endoplasmic reticulum makes?
Membrane proteins and proteins for export out of cell
Smooth endoplasmic reticulum makes?
Makes membrane lipids(steroids)
Regulates calcium (muscle cells)
Destroys toxic substances (liver)
The main difference between rough and smooth endoplasmic reticulum is?
Presence of ribosomes on the surface of rough endoplasmic reticulum
Ribosomes are made up of ___&___
Proteins
rRNA
Function of ribosomes is
Protein synthesis
Ribosomes are either attached to the _____ or free in the ____
Rough ER
Cytoplasm
Sacks of flattened sacks having a CIS face and a TRANS face is called?
Golgi bodies
The shipping side of Golgi bodies is called?
CIS face
The receiving side of Golgi bodies is called?
Trans face
Function of Golgi bodies is?
Modify, sort and package molecules from ER for storage or transport out of the cell
Materials are transported from the Rough ER to Golgi bodies to the cell membrane by ____
Vesicles
Two functions of lysosomes are?
Break down food, bacteria and worn out cell parts
Programmed for cell death(Apoptosis?
Function of cilia/flagella is?
Moving cells, fluids or small particles across the cell membrane
___ are shorter and more numerous on cells
Cilia
___ are longer and fewer on cells(usually 1-3)
Flagella
The basic functional and structural unit of various tissues and organs is called?
Cell
The human body has ____ cells
75-100 trillion
The chemical composition of the cell is?
Water(70-85%) Proteins(10-20%) Ions(sodium, potassium etc) Lipids(2%) Carbohydrates
The chemical composition of cell membrane is
Proteins(55%)
Lipids(42%)
Carbohydrates(3%)
The cell membrane is about ___ in size
75-100A°
Classification of cell membrane proteins are?
Structural proteins(glycoproteins & lipoproteins)
Pumps( transport ions across the membrane)
Receptors( binds hormones and neurotransmitters)
Carriers(transport various substances by facilitated diffusion)
Enzymes(peripheral proteins)
Ion channels(integral proteins)
G
Cell or plasma membrane Lysosome Ribosome Endoplasmic reticulum Nucleus Golgi bodies Centrioles Mitochondria
In the fluid mosaic model of cell membrane, FLUID depicts
Free movement of phospholipids and proteins within the membrane like a liqiud
In the fluid mosaic model of cell membrane, MOSAIC depicts
The pattern produced by the scattered protein molecules when the membrane is viewed from above
The type of transport in the cell membrane that doesn’t require energy and moves due to gradient is called?
Passive Transport
Examples of gradient are?
Concentration
Pressure
Charge etc
Types of passive transport are?
Diffusion
Osmosis
Facilitated diffusion
The movement of molecules to equalise gradient (high to low)
Diffusion
The movement of fluid from lower concentration to higher concentration through semi-permeable membrane is?
Osmosis
Solvent + Solute =?
Solution
A solution that has more solutes in the cell than outside is called?
Hypotonic solution (outside solvent flows into the cell)
A solution that has equal amount of solutes inside and outside of the cell is called?
Isotonic solution
A solution that has more solutes outside the cell than inside is called?
Hypertonic( fluid will flow out of the cell)
The transport of molecules and ions via transmembrane integral proteins(channels? through differentially permeable membrane is called?
Facilitated diffusion
Process of facilitated transport includes
Protein binds with molecules
Shape of protein changes
Molecules move across membrane
The type of transport that requires energy is called?
Active transport
Two types of active transport are?
Primary active transport
Secondary active transport
Materials transported by active transport are either in ____ or ____
Ionic form(sodium, potassium, calcium etc) Non-ionic form(glucose, amino acid etc)
The type of active transport in which energy is liberated directly from ATP breakdown is called?
Primary active transport
Active transport of sodium requires ___
sodium-potassium ATPase pump
Sodium potassium ATPase pump has 2 subunits namely?
Alpha subunit
Beta subunit
Sodium potassium pump has 6 receptor sites namely?
3 receptor sites for sodium ion from the inner surface
2 receptor sites for potassium ion from the outer surface
1 receptor site for the enzyme ATPase
Calcium is transported by the?
Calcium pump(obtains energy from ATP breakdown)
Calcium pumps are present in____ of all cells and mitochondria
Sarcoplasmic reticulum
Hydrogen is transported by?
Hydrogen pump(obtains energy from ATP breakdown)
Hydrogen pump is present in organs like?
Stomach(parietal cells of gastric glands)
Kidney(in epithelial cells of distal tubules
The type of active transport in which substances are transported with sodium ion by means of a carrier protein in the same or opposite direction is called?
Secondary active transport
Two types of secondary active transport are?
Cotransport
Countertransport
A carrier protein that transports 2 different molecules in the same direction across the cell membrane is called?
Symport
Example of Symport is?
Transport of sodium and glucose
Transport of sodium and amino acids
A carrier protein that transports 2 different molecules in opposite direction across the cell membrane is called?
Antiport
Example of Antiport is?
Sodium calcium countertransport
Sodium magnesium countertransport
Sodium hydrogen countertransport
Three special types of active transport are?
Endocytosis
Exocytosis
Transcytosis
Special active transport move large materials like?
Particles
Organisms
Large molecules
Movement of large molecules into cells is called?
Endocytosis
Two types of endocytosis are?
Bulk-phase(non-specific)
Receptor-mediated(specific)
The process of endocytosis include?
Plasma membrane surrounds material
Edges of membrane meet
Membranes fuse to form vesicle
Two forms of endocytosis are?
Phagocytosis(cell eating)
Pinnocytosis(cell drinking)
Movement of large molecules out of cell is called?
Exocytosis
Process of exocytosis is?
Vesicle moves to cell surface
Membrane of vesicle fuses
Molecules expelled
The communication between neighbouring cells or the contact between the cell and the extracellular matrix is called?
Cell junction
Three types of cell junctions are?
Occluding junctions
Anchoring junctions
Communicating junctions
The cell junction that seals cells together into sheets(forming an impermeable barrier) is
Occluding junction/tight junctions
The cell junction that attach cells and their cytoskeleton to other cells or extracellular matrix (providing mechanical support) is?
Anchoring junctions
The cell junction that allows exchange of chemical/electrical information between cells is called?
Communicating junctions
Cell to cell connections are mediated by?
Cadherins
Cadherins participate in?
AdherenS junctions
Tight junctions proteins are?
Claudin
Occludin
___ allow cells to exchange electrical/chemical signals
Gap junctions
Gap junctions channels subunits are?
Connexins
Connexins assemble together to form?
Connexons
Connexons from two cells form a?
Gap junction
How do cells alter their connections to other cells?
Alter the profile of cytoskeletal connections, receptors and extracellular matrix
Alter the binding affinity of receptors
Receptors are mostly ____ dependent
Ca2+
Receptors are mostly affected by____
Protein kinases
___ joins the intermediate filaments in one cell to those in a neighboring cell
Desmosome
___allows passage of small water soluble ions and molecules
Gap junction
____ anchors intermediate filaments in a cell to the basal lamina
Hemidesmosome
___ seals neighboring cells together in an epithelial sheet to prevent leakage of molecules between them
Tight junction
___ allow cells to exchange electrical/chemical signals
Gap junctions
Gap junctions channels subunits are?
Connexins
Connexins assemble together to form?
Connexons
Connexons from two cells form a?
Gap junction
How do cells alter their connections to other cells?
Alter the profile of cytoskeletal connections, receptors and extracellular matrix
Alter the binding affinity of receptors
Receptors are mostly ____ dependent
Ca2+
Receptors are mostly affected by____
Protein kinases
___ joins the intermediate filaments in one cell to those in a neighboring cell
Desmosome
___allows passage of small water soluble ions and molecules
Gap junction
____ anchors intermediate filaments in a cell to the basal lamina
Hemidesmosome
___ seals neighboring cells together in an epithelial sheet to prevent leakage of molecules between them
Tight junction
____ is also known as zona occludenn
Tight junction
The two types of proteins involved in the formation of tight junctions are?
Integral membrane proteins: occludin,claudin, JAM’s
Scaffold proteins:cinguilin,symplekin
JAM’s mean?
Junctional adhesion molecules
Four functions of tight junctions are?
Strength and stability
Fencing function
Blood-brain barrier
Selective permeability
Four disease caused by tight junction protein’s genes mutations are?
Hereditary deafness
Ichthyosis (scary skin)
Synovial sarcoma (soft tissue cancer)
Sclerosing cholangitis (inflammation of bile ducts?
Two types of anchoring junctions are?
Actin filament attachment
Intermediate filament attachment
Two types of actin filament(MF) attachment are?
Cadherins (cell to cell) Focal adhesion (cell to matrix)
Two types of intermediate filament(IF) attachment are?
Desmosomes (cell to cell)
Hemidesmosomes(cell to matrix)
Dysfunction of the cadherins and focal adhesion junctions due to protein mutations causes ___&___
Colon cancer
Tumor metastasis
Dysfunction of hemidesmosomes causes?
Bullous pemphigoid
Connexons are either___ or ___
Homomeric
Heteromeric
Gap junction intercellular channels are either____ or ____
Homotypic
Heterotypic
Three functions of gap junctions include?
Exchange of chemical messengers between the cells
Rapid propagation of action potential from one cell to another
Allows passage of glucose, amino acids and other substances with a molecular weight less than 1000
Factors that regulate the diameter of gap junctions are?
pH
Electrical potential
Hormones or neurotransmitters
Calcium ion concentration
Mutations of genes encoding connexins causes diseases like?
Deafness Keratoderma Cataract Peripheral neuropathy Heterotaxia
Maintenance of a relatively stable internal environment is called?
Homeostasis
Maintenance of homeostasis is carried out by?
Nervous system
Endocrine system
The nervous system regulates homeostasis by?
Controlling and coordinating bodily activities that require rapid responses
Detects and initiates reactions to changes in external and internal environment
The endocrine system regulates homeostasis by?
Releasing hormones
Homeostasis is continuously disrupted by?
External stimuli (heat, cold, toxins etc) Internal stimuli(body temperature, blood pressure, water and glucose concentration etc)
Components of homeostasis system are?
Sensors) receptors Comparator/control centre Effectors Feedback control Communication system
Sensors) receptors detects?
Changes in the internal environment
Comparator/control centre fixes?
The set point of the system
The function of effectors is to?
Bring the system back to the set point
Two types of feedback control are?
Positive feedback
Negative feedback
Positive feedback/positive feedback loop ____ the original stimulus
Intensifies/increases
Negative feedback/negative feedback loop ____ the original stimulus
Reverses/shuts off
Example of positive feedback loop is?
Childbirth
Example of negative feedback loop is?
Most feedback systems in the body eg blood pressure
A homeostatic control system must be able to?
Receive signal from the receptor
Integrate this information with other relevant information
Send a signal to the appropriate organ or gland to make the necessary adjustment
Sense deviations from the norm itself
The general control centre for homeostasis is the?
Brain(hypothalamus)
The pancreas is it’s own control centre for blood sugar
___ are responses made after change has been detected
Feedback
In blood pressure system (negative feedback) march the following? Stimulus-\_\_\_ Receptor/sensor-\_\_\_ Control centre/comparator-\_\_\_ Effector-\_\_\_
Blood pressure
Baroreceptors
Brain(hypothalamus)
Heart
