Cells Flashcards
They carry out all chemical activities needed to sustain life.
Cells and Tissues
They are the building blocks of all living things.
Cells
They are groups of cells that are similar in structure and function.
Tissues
Anatomy of the Cell:
- Cells are not all the same
- All cells share general structures
Cells are organized into three main regions:
- Nucleus
- Cytoplasm
- Plasma membrane
It is the control center of the cell; it contains genetic material (DNA).
Nucleus
The 3 regions of the nucleus:
- Nuclear membrane
- Nucleolus
- Chromatin
It is the barrier of the nucleus consisting of a double phospholipid layer.
Nuclear membrane
It contains nuclear pores that allow for the exchange of material with the rest of the cell.
Nuclear membrane
The nucleus contains one or more _________.
nucleoli
It is the site of ribosome production; ribosomes then migrate to the cytoplasm through nuclear pores.
Nucleoli
It is composed of DNA and protein and is scattered throughout the nucleus.
Chromatin
Chromatin condenses to form ____________ when the cell divides.
chromosomes
The barrier for cell contents; contains protein, cholesterol, and glycoproteins.
Plasma membrane
The plasma membrane consists of a double phospholipid layer which has:
- Hydrophilic heads
- Hydrophobic tails
Polar heads that are attracted to water.
Hydrophilic heads
Nonpolar fatty acid tails that avoid water and line up in the center of the membrane.
Hydrophobic tails
Finger-like projections that
increase surface area for absorption.
Microvilli
The 3 membrane junctions are the following:
- Tight junctions
- Desmosomes
- Gap junctions
These are impermeable junctions
that encircle the cells and bind them together into leakproof sheets. (Found in the small intestine)
Tight junctions
These are anchoring junctions scattered like rivets along the sides
of adjacent cells. They prevent cells subjected to mechanical stress (such as heart muscle cells and skin cells) from being pulled apart.
Desmosomes
They function mainly to allow communication. These junctions are commonly found in the heart and between embryonic cells.
Gap junctions
These are hollow cylinders composed of proteins that connect neighboring cells.
Connexons
Material outside the nucleus and inside the plasma membrane; the factory of the cell.
Cytoplasm
Fluid that suspends other elements.
Cytosol
Metabolic machinery of the cell.
Organelles
Non-functioning units
Inclusions
They are made of protein and RNA; the sites of protein synthesis.
Ribosomes
Ribosomes are found in:
- Free in the cytoplasm
- Attached to the rough endoplasmic reticulum
Fluid-filled tubules for carrying substances.
Endoplasmic reticulum
The 2 types of Endoplasmic reticulum are:
- Rough endoplasmic reticulum
- Smooth endoplasmic reticulum
It is studded with ribosomes; where building materials of cellular membranes are formed.
Rough endoplasmic reticulum
Functions in cholesterol synthesis and breakdown, fat metabolism, and detoxification of drugs.
Smooth endoplasmic reticulum
Modifies and packages proteins.
Golgi apparatus
They carry substances around the cell.
Transport vesicles
The different types of packages produced by the Golgi apparatus are the:
- Secretory vesicles
- Cell membrane components
- Lysosomes
Contain enzymes that digest nonusable materials within the cell.
Lysosomes
Characteristics of Peroxisomes:
- Membranous sacs of oxidase enzymes
- Detoxify harmful substances
- Break down free radicals
- Replicate by pinching in half
These are highly reactive chemicals with unpaired electrons that can damage the structure of proteins
and nucleic acids.
Free radicals
Peroxisomes convert free radicals to ___________, then its excess into water.
hydrogen peroxide
Peroxisomes are especially numerous in _____ and _____ cells,
which are very active in detoxification.
liver and kidney cells
They are the “powerhouses” of the cell; they carry out reactions where oxygen is used to break down food
and provide ATP for cellular energy.
Mitochondria
Network of protein structures that extend throughout the cytoplasm
; provides the cell with an internal
framework.
Cytoskeleton
The cytoskeleton is made up of the following:
- Microfilaments
- Intermediate filaments
- Microtubules
These are most involved in cell motility and in producing changes in cell shape. (Myosin and actin)
Microfilaments
They are made up of fibrous subunits. They help form desmosomes and provide internal guy wires to resist pulling forces
on the cell.
Intermediate filaments
They are made up of repeating subunits of the protein tubulin.
They determine the overall shape of a cell and the distribution of organelles.
Microtubules
Rod-shaped bodies made of microtubules; direct formation of the mitotic spindle during cell division.
Centrioles
Centrioles are collectively called _________.
centrosome
They are not found in all cells; used for movement.
Cellular projections
Moves materials across the cell surface.
Cilia
It propels the cell.
Flagellum
Cells that connect body parts:
- Fibroblast
- Erythrocyte (RBC)
Cells that cover and line body organs:
Epithelial cell
Cells that move organs and body parts:
Skeletal muscle cell
Cardiac muscle cell
Smooth muscle cell
Cell that stores nutrients:
Fat cell/Adipose cell
Cell that fights disease:
White blood cells (macrophage)
Cell that gathers information and controls body functions:
Nerve cell/Neuron
Cells of reproduction:
- Oocyte (Female)
- Sperm (Male)
Movement of substances into and out of the cell.
Membrane transport
A homogeneous mixture of two or more components.
Solution
The dissolving medium
Solvent
The one that is being dissolved; is present in smaller amounts.
Solute
Does not require energy for transport.
Passive transport
It is a solution containing
small amounts of gases, nutrients, and salts, dissolved in water. (Collectively, the nucleoplasm and the cytosol)
Intracellular fluid
The fluid that continuously bathes the exterior of our cells. (“Unusual soup”)
Extracellular/Interstitial fluid
A barrier (plasma membrane) allows some substances to pass through it while excluding others.
Selective permeability
The fat-soluble vitamins are:
Vitamins A, D, E, K
Molecules move from areas of high concentration to areas of low concentration.
Diffusion
The greater the difference in concentration between the two areas, the _____ diffusion occurs.
faster
The unassisted diffusion of solutes through the plasma membrane.
Simple diffusion
Diffusion of water through a selectively permeable membrane.
Osmosis
It provides passage for certain needed substances (notably glucose) that are both lipid insoluble and too large to pass through the membrane pores.
Facilitated diffusion
Highly polar water is repelled by the nonpolar lipid core of the plasma membrane, but it can pass easily through special pores called
__________.
aquaporins
It pushes solute-containing fluid
(filtrate) from the higher-pressure area through the filter to the lower-pressure area.
Filtration
It is the process by which water and solutes are forced through a membrane (or capillary wall) by fluid, or hydrostatic, pressure.
Filtration
A cell uses ATP to move substances
across the membrane; unable to pass through diffusion.
Active transport
Active transport uses ATP to energize its protein carriers, which are called _________.
solute pumps
It alternately carries sodium ions out of potassium ions into the cell.
Sodium-potassium pump
The phosphate is attached to the sodium-potassium pump.
Phosphorylation
It involves help from ATP to fuse or separate membrane vesicles and the cell membrane and moves substances into or out of cells “in bulk” without crossing the plasma membrane directly.
Vesicular transport/Bulk transport
The 2 types of vesicular transport are:
- Exocytosis
- Endocytosis
It is the mechanism that cells use to actively secrete hormones, mucus, and other cell products.
Exocytosis
Includes those ATP-requiring processes that engulf extracellular substances by enclosing them in a vesicle.
Endocytosis
“Cell eating”; is a protective mechanism—a way to “clean house”—not a means of getting nutrients.
Phagocytosis
“Cell drinking”; the cell “gulps” droplets of extracellular fluid.
Pinocytosis
In this process, receptor proteins on the plasma membrane bind exclusively with certain substances.
Receptor-mediated endocytosis
The same solute and water concentrations; cause no visible changes in cells.
Isotonic
A solution that contains more solutes than there are inside the cells - the cells begin to shrink.
Hypertonic
Hypertonic solutions are sometimes given to patients
who have ______.
Edema (swelling of the feet and hands due to fluid)
A solution contains fewer solutes and therefore more water than the cell does - cells begin to swell.
Hypotonic
It represents the most extreme example of a hypotonic fluid.
Distilled water
They are sometimes infused intravenously (slowly and with care) to rehydrate extremely
dehydrated patients.
Hypotonic solutions
The 2 major periods of cell life cycle are:
- Interphase
- Cell division
The cell grows and carries on its metabolic activities.
Interphase
The cell is very active and is preparing for cell division (metabolic phase).
Interphase
The cell reproduces itself.
Cell division
It is the process of dividing a
nucleus into two daughter nuclei with the same genes as the “mother” nucleus.
Mitosis
As cell division begins, the chromatin threads coil and shorten.
Prophase
Each chromosome is actually
made up of two identical strands called _________.
sister chromatids
Holds together the chromatids; buttonlike body.
Centromere
Centrioles separate from each other and move toward opposite sides of the cell assembling the _________.
mitotic spindle
The chromosomes line up at the metaphase plate.
Metaphase
Centromeres that have held the chromatids together split. The chromatids (now called chromosomes again) begin to move slowly apart, drawn toward opposite ends of the cell.
Anaphase
Prophase in reverse. The chromosomes at opposite ends of the cell uncoil to become
threadlike chromatin again. The spindle disappears, and a nuclear envelope forms.
Telophase
A DNA segment that carries the information for building one protein.
Gene
Each sequence of a _______ calls for a particular amino acid.
triplet (three bases)
It is a messenger that carries the instructions for building proteins to the ribosomes.
RNA
It helps form the ribosomes, where proteins are built.
Ribosomal RNA (rRNA)
They carry instructions for protein synthesis from the DNA in the nucleus to the ribosomes in the cytoplasm.
Messenger RNA (mRNA)
These molecules are small,
cloverleaf-shaped molecules that escort amino acids to the ribosome.
Transfer RNA (tRNA)
The transfer of information from the sequence of bases in a DNA gene into the complementary sequence of mRNA by an enzyme.
Transcription
The three-base sequence in DNA.
Triplet
The three-base sequence in RNA.
Codon
A phase of protein synthesis; the
language of nucleic acids (base sequence) is translated into the language of proteins (amino
acid sequence).
Translation
Translation occurs in the ________ and involves three major varieties of RNA.
cytoplasm
A special three-base sequence that can temporarily bind to the complementary codons.
Anticodon
