Cells Flashcards
Cell
Smallest structural and functional unit of any living thing
Cell membrane
Phospholipid bilateral, plasma membrane.
Surrounds the cell and differentiates what is inside the cell and outside the cell.
Hydrophilic
Water loving
Hydrophobic
Water avoiding
Membrane proteins
Proteins embedded in the cell membrane. Substance- specific, designed to interact only with one particular substance and no other.
Name the 4 passive processes
Diffusion
facilitated diffusion
Osmosis
Filtration
What is a passive process?
Passive processes get substances in or out of the cell by using kinetic energy of the substance crossing the membrane. No energy is needed from the cell
Diffusion
The movement of a substance from an area of higher concentration to lower concentration .
Oxygen and carbon dioxide can diffuse.
Ex- there is more oxygen outside than inside the cell, kinetic energy of oxygen mole uses will cause the oxygen to diffuse down the concentration gradient.
Osmosis
The diffusion of water.
If there are more sodium ions outside than inside the cell, there will be a higher concentration of water inside the cell. By osmosis, the water molecules will move down the concentration gradient and out of cell.
Facilitated Diffusion
Membrane proteins called channels, gates and carriers provide passage for molecules and ions that are too big to freely diffuse across cell membrane
Cell channel
Provide pathway for small substances like sodium. Sometimes pocess a ‘door’ that opens and closes in which they are called gates.
Carriers/Transporters
Change shape to pass larger molecules like glucose across the cell membrane.
Receptors
Receive information (hormones and neurotransmitters) from outside the cell and use it to direct activity inside the cell. Ex- insulin receptors tell the cell to start facilitated diffusion of glucose (through carriers).
Filtration
Water is pushed through a specialized cell membrane that has large pores (cells of the kidneys) allowing small substances to pass through with the water and keeping large molecules behind.
Active processes
Require the expenditure of energy by the cell to get a substance in and out across the membrane.
Active process
The movement of ions or small molecules up a concentration gradient ( from an area of lower concentration to an area of higher concentration) by membrane proteins called pumps. Requires energy from the cell
Endocytosis
A process where a cell uses energy to bring particles in that are too large for facilitated diffusion.
Phagocytosis “cell eating”
Pinocytosis “cell drinking”
Phagocytosis
The cell surrounds the substance with pseudopodia (“false feet”) and brings it into the cell
Pinocytosis
“Cell drinking”. The cell membrane invaginates to bring particles into the cell.
An endosome is created when the cell membrane encircles the particles into the cell.
Exocytosis
The cell uses energy to get substances out by forming a membrane around a substance inside the cell and then merging to the cell membrane and emptying contents outside the cell.
Excretion
During exocytosis, if the substance being exocytosed is waste, it is excreted
Secretion
During exocytosis if the substance being exocytosed is a product synthesized in the cell, it is secreted
Organelles
Organs of the cell which perform specific functions.
Lysosome
Once a substance is brought into a cell and contained in an endosome, it may be sent to a lysosome to be broken down into usable parts.
Lysosomes contain enzymes to act like the ‘stomach’ of the cell.
Break down substances brought into the cell.
Enzymes
Proteins that act as catalysts for chemical reactions, often by breaking chemical bonds.
Ensoplasmic Reticulum
A maze-like network of membranes in the cell.
Rough ER
Generally found closer to the nucleus and is lined with ribosomes, the tiny organelles where protein synthesis occurs.
Smooth ER
Generally found close to the cell membrane and is responsible for the production of lipids.
Nucleus
Containes the genetic material of the cell (DNA)
DNA
Deoxyribonucleic Acid. The information required for a cell’s structure and function, including the instructions for creating every type of protein That exists in the body.
Nucleolus
The center of the nucleus where ribosomes are made.
Nuclear Envelope
A double-layer membrane surrounding the nucleus. It has pores that allow substances to enter and exit the cell
Gogli Complex
Gogli aparatus. Package proteins to be shipped out of cell.
After protein synthesis, proteins are sometimes delivered to gogli aparatus which is like a post office. They arrive either directly from the rough ER or via transport vesicles, bubble-like detachments of the membrane system.
Secretary Vesicles
Packaged proteins leave the gogli complex in secretary vesicles through secretion
Mitochondria
Organelles that produce energy for the cell. Enzymes on the inner surface of a mitochondrion’s folded membrane facilitate the oxidation of glucose to produce ATP (adenosine triphosphate)
ATP is the main energy storage and distribution mechanism for the cell.
ATP
Adenosine triphosphate. The principle energy storage and distribution mechanism for the cell.
ATP is created through cellular respiration (metabolic process that breaks down glucose)
Its the energy ‘currency of the cell
ATP can be broken down to release energy for the cell to us, or ATP can be created (cellular respiration) to store energy for later.
The more ATP molecules a cell has, the more energy is has available.
ATP is formed by adding phosphates to molecules of ADP (adenosine diphosphate)
Energy is stored in the bind between the ADP molecule and the phosphate
(ADP + energy + P = ATP)
Cytoskeleton
The freely moving organelles of the cell that provide structure to the cell and allow movement.
Microtubules
The supporting framework or the cell. The ‘bones’
Microfilaments
Similar to the muscles of the human body. Microfilaments are contraction proteins that produce the internal movements of the cell
Cilia
Hairlike projections of the cell membrane that move the substances over a cell’s surface.
Flagella
The longer, less numerous whip-like extensions that move the cell itself.
Microvilli
Microscopic, fingerlike undulationd of the cell membrane line that increase the cell’s surface area to allow greater absorption
Cellular Metabolism
All of the chemical reactions and processes that occur within a cell in order to sustain life.
Two types of metabolism
Anabolism
Catabolism
Anabolism
The cell uses energy to build complex molecules from simple components.
Catabolism
Breaking down Organic substances to gain energy for use in the cell or to get raw materials.
Metabolic rate
Rate at which a cell or organism uses energy to undergo catabolism and anabolism
Amino Acids
Building blocks of proteins.
Proteins
Large organic molecules that form most of the mechanical apparatuses in cells, as well as many extracellular substances like the fires of connective tissue. Made up of amino acids.
Protein synthesis
Anabolic process by which cells assemble sequences of amino acids to make proteins.
The creation of proteins. Directed by nucleic acids.
Nucleic Acids
Directs the process of protein synthesis
DNA RNA mRNA tRNA RRNA
Gene
A segment of DNA with instructions for making a protein.
Nitrogen Bases
The ladder rungs of DNA. Complementary pairs of
Guanine and Cytosine
Adenine and Thymine
Triplet
A sequence of 3 nitrogen bases in DNA. The 3 letter ‘words forms instructions that tell the cell which amino acids to string together to make a specific protein.
Transcription
mRNA makes a copy of the gene to be sent to the ribosome, where the protein is assembled.
The DNA molecule within the nucleus partially unzips, exposing the bases and allowing RNA nucleotides to form a complementary strand of mRNA along one of the exposed strands of DNA.
The DNA is transcribed into a 3 base sequence called codons on the mRNA.
A copy of the language transcribed from the DNA.
mRNA then leaves the nucleus through a nuclear pore to carry the copy of the amino acid sequence to a ribosome.
tRNA
Transfer RNA molecules pick up the amino acids that are needed to synthesize (build) proteins and bring them to the ribosome. The tRNA has a 3 base sequence called an anticodon which determines which amino acids are picked up.
Translation
When the tRNA and mRNA meet at the ribosome.
The mRNA threads through the ribosome and a tRNA carrying the amino acids ugs its anticodon into a conplemtary codon on the strain of mRNA.
A second tRNA plugs into the next codon. The first tRNA is released leaving behind its amino acid that bonds to the second amino acid by peptide bond.
Polypeptide chain
The result of translation, the primary structure of a protein made up of amino acids.
Cellular respiration
Catabolism. Metabolic process in which the cell breaks down glucose in order to create ATP (adenosinetriphosphate) the energy currency of the cell.
Glycolysis, the splitting of sugars and first stage of cellular respiration. (Anaerobic respiration)
A 6 carbon glucose molecule is split into two three-carbon molecules of pyruvic acid in the cytoplasm of the cell.
Energy release from this reaction is captured to form two molecules of ATP.
In the absence of oxygen, the pyruvic acid degrades into lactic acid and the process is finished.
Aerobic respiration
The second stage of cellular respiration. Oxygen is available in the cell.
A series of chemical reactions known as the Krebs cycle and the electron transport chain, which together create 36 additional ATP.
