Cells at work Flashcards
Fluid mosaic model
- maintain shape
- Coordinate changes thru attachment to the cytoskeleton and extracellular matrix
- Chemical messengers (signal transduction)
- Cell recognition (glycoproteins)
- Selective Permeability
Diffusion w/o energy investment or movement of molecules to its own gradient.
Passive transport
Diffusion of molecules to
selective permeable membrane
Osmosis
The ability of surrounding solution to cause a cell to gain or lose water.
Tonicity
Low solute level
Hypotonic
Equal solute level
Isotonic
Higher solute level
Hypertonic
It means the control of water balance
Osmoregulation
A type of passive transport but uses proteins to move across a membrane.
Facilitated Diffusion
The very rapid diffusion of water into and out of certain cells
Aquaporin
The movement of ions or molecules across
a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy.
Active Transport
The energy needed for Active Transport
Adenosine Triphosphate (ATP)
It is the transfer of Phosphate
Phosphorylation
It refers to the release of energy. Most of the metabolism are this kind of reaction
Exergonic reaction
It requires a net input of energy and yield products that are rich in potential energy
Endergonic reaction
It is the use of energy released from exergonic reaction to drive endergonic reactions
Energy coupling
It refers to the energy barrier that must be overcome before a chermical reaction can begin
Activation Energy
It binds to the active site and function in catalysis
Cofactors (nonprotein helpers)
It reduces enzyme’s productivity by locking the substrate molecules
Competitive Inhibitor
It does not enter the active site. Instead, it binds to the enzyme somewhere else called an allosteric site
Noncompetitive Inhibitor
Model that describes the parental strand rejoins after replication
Conservative Model
The model that describes that the parental DNA double helix is broken into segments that act as templates
Dispersive Model
The model that describes that two parental DNA strands separate and each of those strands then serves as a template for the synthesis of a new DNA strand
Semi-conservative Model
It refers to the “unzipping” of double stranded molecule done by DNA helicase (disrupts hydrogen bond).
Initiation
The area that will become the template for replication
Replication Fork
It holds the unpaired DNA strand
Single-stranded binding protein
The process of creating new strand of DNA by adding nucleotides to template strands.
Elongation
The main function of this is to duplicate the DNA content of a new cell during cell division
DNA Polymerase
The process of ending transcription
DNA Termination
The two types of RNA
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
It contains the genetic message transcribed from the DNA
Messenger RNA (mRNA)
It is the general term for the synthesis of any kind of RNA from DNA
Transcription
A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth
Mitosis
A type of cell division that produces four sex cells or gametes with half the number of chromosomes of the original cell.
Meosis
- Chromatin condenses: DNA coils up.
- Centrioles move apart.
- Microtubules form the spindle.
Prophase
- Nuclear membrane dissolves.
- Proteins form Kinetochores on centromeres.
- Fibers attach to Kinetochores.
- Chromosomes move toward the center.
Prometaphase
- Spindle fibers align chromosomes.
- Forms the metaphase plate (straight line).
- Ensures proper chromosome separation.
- Each daughter cell gets one copy.
Metaphase
- Chromatids separate at kinetochore.
- Move to opposite ends.
- Kinetochore action and polar microtubule interaction drive movement.
Anaphase
- Chromosomes reach opposite ends.
- Chromosomes expand.
- Formation of the nuclear membrane starts.
- Spindle fibers disappear, and cytokinesis begins.
Telophase
- Separation of two daughter cells.
- Actin protein forms a fiber ring in the center.
- Pinches the cell, resulting in two diploid (46 chromosomes) daughter cells.
Cytokinesis
- Chromosomes match in homologous pairs.
- Somatic cells have a species-specific chromosome count; e.g., humans have 46.
- Composed of 23 pairs of homologous chromosomes.
- These chromosome pairs may carry different versions of the same gene.
- X and Y chromosomes are only partially homologous.
Meosis
