Biochemistry Flashcards
Ionic Bonds
Occur when atoms either donate or accept electrons from another atom.
What are the three types of chemical bonds?
- Covalent
- Ionic
- Hydrogen
Cation
The atom that DONATES an electron in an ionic bond becomes POSITIVE (+).
Anion
The atom that ACCEPTS an electron in the ionic bond becomes NEGATIVE (-).
Salts
When an ionic bond forms between mineral compounds.
Electrolytes
Salts able to transmit electrical energy that are important in biochemical processes.
When dissolved in water, what do acids release?
Hydrogen ions
When dissolved in water, what do bases release?
Hydroxyl ions
____ occur when two atoms each have an unpaired electron in their outer orbitals.
Covalent bonds!
• Each atom exerts a force on the unpaired electron of the other, pulling them together.
• The unpaired electrons are then shared.
___ is the sharing of electrons equally in a covalent bond.
Nonpolar bond
Polar covalent bond
Unequal sharing of electrons between two atoms causing one end of the molecule to have a slight positive charge and the other end to have a slight negative charge. WATER!
Properties of water
- Water is the universal solvent.
- Water is an ideal transport medium.
- Water has a high heat capacity and a high heat of vaporization.
- Water is used for lubrication.
Hydrogen bonding
Occurs when there’s a weak attraction between a slightly negative atom in a polar covalent bond and a slightly positive hydrogen atom involved in a second polar covalent bond.
Cohesion of water molecules results in:
High surface tension of water.
Adhesion refers to:
The attraction between water molecules and other charged surfaces.
Types of compounds:
Inorganic and organic
Inorganic compounds
Those that don’t contain hydrocarbons (carbon and hydrogen bonded) together, such as salts and water.
Organic compounds
- Characterized by the presence of hydrocarbons.
- The hydrocarbon groups are usually bonded to another group of atoms known as the functional group that’s unique to each type of organic compound.
Types of organic compounds
- Carbohydrates
- proteins
- lipids
- nucleic acids
Carbohydrates
- Consist of carbon, hydrogen, and oxygen in a 1:2:1 ratio.
* Cells use them for energy as well as structural materials.
Three classes of carbohydrates:
- Monosaccharides
- Oligosaccharides
- Polysaccharides
Monosaccharides
Simple sugars composed of only one monomer. Examples are glucose fructose and ribose.
Oligosaccharides
Short chains of sugar monomers covalently bonded together. If they contain only two sugar monomers, they are known as disaccharides. Examples of disaccharides are lactose (milk sugar) and sucrose (table sugar).
Polysaccharides
Complex carbohydrates with many sugar monomers that form chains or branches. These monomers may be of different types and may number in the thousands. Examples include glycogen, starch, and cellulose.
Lipids
- Fats and other oily substances.
- Cells use them for energy storage, structural support, and as signaling molecules.
- Composed of fatty acids attached to glycerol.
Proteins
- Form enzymes and hormones and control all metabolic and biochemical reactions and processes in cells.
- Composed of chains of amino acids joined by peptide bonds.
There are ___ different amino acids in the body that contain a ___ bound to an ___, a ___, and a ___.
20 Carbon atom Amino group Carboxyl group Side chain (R)
A protein’s secondary structure is formed by___.
Hydrogen bonds at intervals along the length of the amino acid chain that cause it to coil or bend.
___ causes further bending and looping of the protein and makes up its third structural level.
Bonding of certain amino acids
The fourth level of protein structure is reached when___.
Hydrogen bonds or bonds between R groups join two or more polypeptide chains together.
The process of transcribing and translating the genetic message into a protein requires the molecule___.
Ribonucleic acid
Enzymes
Proteins that act as catalysts to speed up the rate of a metabolic reaction.
Small organic compounds that contain one or more phosphate groups and a five carbon sugar attached to a nitrogenous base are called___.
Nucleotides
Example: ATP
The phosphate bonds of ATP contain energy that’s released when enzymes break off ATPs outer phosphate group and attach it to another molecule by the process known as___.
Phosphorylation
The bases in DNA are:
- Adenine
- Guanine
- Cytosine
- Thymine
The bases in RNA are:
- Adenine
- Guanine
- Cytosine
- Uracil
Characteristics of DNA:
- DNA exists as a double-stranded molecule.
- Twisted into a double helix.
- Bases always link in either adenine-thymine or cytosine-guanine pairs.
Characteristics of RNA:
- Single-stranded molecule
2. Three types: messenger RNA, ribosomal RNA, transfer RNA
The first step in protein synthesis is___.
Transcription; enzymes bind to the DNA molecule at the location of a gene to unwind and uncoil the molecule.
A ___ marks the end of a gene.
Stop sequence.
Protein synthesis occurs at the___.
Ribosome
Each of the 20 amino acids found in proteins of living things has a specific set of base triplets referred to as a ___ on the mRNA.
Codon
___ are changes in DNA that can result in abnormal protein synthesis.
Mutations
Types of mutations:
- Point mutations– one nitrogen base is substituted for another.
- Nonsense mutations– A change in a codon for an amino acid into a stop codon occurs.
- Frameshift mutations– Nucleotide bases are either added or deleted, causing a change in the entire sequence of amino acids.
___, which carry electrical messages from one region to another, are long and thin.
Nerve cells
___, which produce movement in the body by shortening in length, are long, cylindrical selves packed full of contractile proteins.
Muscle cells
Cell membrane
- The structure surrounding the cell that forms a barrier between the inside of the cell and the outside.
- Composed of a double layer of phospholipids (barrier), which are embedded with protein molecules (channels/carriers).
The outer surface of the cell membrane also contains___, which are structures through which hormones and other chemicals outside of the cell can bind.
Receptors; this binding action signals the cell to carry out particular functions.
Pseudopodia
Fingerlike projections that allow the cell to move around or engulf substances to bring them into the cell.
Mitochondria
- Powerplants of the cell.
* Produce adenosine triphosphate (ATP).
Endoplasmic reticulum
- Forms a network of tubes, channels, and sacs within the cytoplasm that are associated with synthesis and transport of materials within the cell.
- Rough endoplasmic reticulum has ribosomes.
- Smooth endoplasmic reticulum has no ribosomes on it; Produces lipids.
Golgi apparatus
Prepares and packages material for export from the cell.
Lysosomes
Saclike organelles that contain powerful digested enzymes to break down substances within the cell.
Nucleus
- Directs all of the cells activities.
- Surrounded by a nuclear membrane that separates the contents of the nucleus from the cytoplasm.
- Contains DNA.
Chromatin
Threadlike material of DNA found in the nucleus.
Before a cell divides the threadlike chromatin must become condensed or coiled into short, compacted bodies called___.
Chromosomes; single strand of DNA.
Humans have___chromosomes in the nucleus of each cell.
46
Dogs have___chromosomes per cell.
78
Gene
Specific region of a chromosome that codes for a single, particular characteristic.
Nucleolus
Clumps of RNA
The majority of the water present in an animal is found___.
Within cells and is called intracellular fluid.
Water found outside cells is called___.
Extracellular fluid
Extracellular fluid located within tissues is referred to as___.
Interstitial fluid
___helps maintain the concentrations of substances within the intracellular and extracellular compartments.
Plasma membrane
Transport processes used by the cell that may require cellular energy expenditure is known as___.
Active transport
Transport processes used by the cell that do not require cellular energy are known as___.
Passive transport
Examples of passive transport:
· Diffusion
· Facilitated diffusion
· Osmosis
· Filtration
The term___refers to a difference between two areas.
Gradient
______ refer to differences in concentration of substances between two areas.
Concentration gradients
___Describe differences in pressure between two areas.
Pressure gradient
___Describe differences in temperature between two areas.
Temperature gradient
Diffusion
The kinetic movement of molecules from higher to lower concentration.
Facilitated diffusion
Selective carrier proteins assist in movement of molecules from higher to lower concentration; speed of diffusion is limited by saturation of carrier molecules.
Osmosis
Passive movement of water through a semi permeable membrane from dilute solution to more concentrated one.
Examples of active transport:
· Endocytosis
· Exocytosis
Types of endocytosis:
· Phagocytosis
· Pinocytosis
• Receptor mediated
When a cell engulfs solid substances it is called___.
Phagocytosis
When a cell engulfs liquid substances it is called___.
Pinocytosis
When specialized protein receptors bind to ligands specific to receptors it is called___.
Receptor mediated
The excretion of waste products and secretion of manufactured substances is known as___. These substances are packaged in secretory vesicles, which fuse with cell membrane; contents are ejected to the extracellular space.
Exocytosis
Mitosis
Cell division
The stage in the cell’s life when no cell division is occurring is called___.
Interphase
When stimulated to undergo mitosis, the cell first…
Duplicates it’s DNA molecules.
Mitosis involves four phases:
- Prophase
- Metaphase
- Anaphase
- Telophase
Prophase
· The chromosomes begin to coil and condense and become visible as chromosomes, and the nuclear membrane dissolves.
· The spindle fibers form and attach to the chromosomes at their centromeres to control their movement.
Metaphase
The spindle fibers line up all of the chromosomes in the middle of the cell.
Anaphase
The spindles pull the two identical copies of each chromosome apart at the centromere, and the copies are pulled toward opposite ends of the cell.
Telophase
The chromosomes become less condensed, the spindle fibers disappear, and a nuclear membrane reforms around each new set of chromosomes.
When the cell membrane becomes constricted in the middle of the cell between the two nuclei it is called___.
Cytokinesis
A condition in which the cells in bone marrow stop producing blood cells and lead to anemia and leukopenia is called___.
Aplastic anemia
Anemia
Insufficient red blood cells
Leukopenia
A deficiency of white blood cells.
___ organisms are ones that can transform energy from the sun into chemical energy.
Autotrophic
___ organisms are those that transform chemical energy from autotrophic organisms into usable energy for their own cellular work.
Heterotrophic
When ATP loses a phosphate radical in a reaction called ___, then the nucleotide becomes adenosine diphosphate (ADP).
Hydrolysis
How is ATP replenished?
By phosphorylating ADP back to ATP.
___ is the breakdown of a substance.
Catabolism
What is the byproduct of a catabolic reaction?
The production of energy.
The opposite of catabolism is___, which is the construction of more complex compounds from simpler compounds. This reaction needs energy to drive the reaction.
Anabolism
Steps in metabolism:
- Hydrolysis
- Breakdown and absorption of nutrients.
- Glycolysis
- Aerobic respiration
The location on the enzyme molecule that binds with the substrate is referred to as the ___ .
Active site.
____ and ____ may be involved in changing the shape of a molecule to improve the ability of the substrate to bind to the active site.
Cofactors and coenzymes
____ is the most abundant of the monosaccharides and the most important to biological organisms. This compound is produced during photosynthesis and consumed during cellular respiration.
Glucose
In non ruminants, enzymes in salivary glands and the small intestines ____ dietary saccharides and polysaccharides into the monosaccharide glucose.
Hydrolyze; i.e. Split up compounds through the addition of water.
Glucose enters the cells by either _____ or ______.
Active transport
Facilitated diffusion
Within the cells, the glucose molecules are either _____ to produce energy in the form of ATP, or they may be converted to ____ or ____.
Catabolized (broken down)
Glycogen (a large polysaccharide)
Fat
In herbivores (ruminants), the polysaccharide ____ is ingested and broken down to ____, particularly ____. ____ are then used as a source of energy.
Cellulose
Volatile fatty acids (VFAs)
Propionate
VFAs
Cells use the process of ____ to release energy contained within the glucose molecule.
Glycolysis
Where does glycolysis occur?
Within the cytoplasm of the cell.
What does glycolysis produce?
2 molecules of ATP
2 molecules of NAD
1 molecule of pyruvic acid
Glycolysis reactions use a process called ____.
Phosphorylation; which involves binding phosphate groups into the carbon groups of the glucose molecules.
_____ occurs in the presence of oxygen in cells that contain mitochondria.
Cellular respiration
Energy pathways that occur in the absence of oxygen:
Alcoholic fermentation & Lactic acid fermentation
Lipids are primarily metabolized in ____ cells.
Liver
Protein metabolism occurs mainly in the ____, ____, ____, and ____.
Brain
Liver
Kidney
Skeletal muscle cells
Proteins can be catabolized by ____.
Deamination aka transamination
The binding of sodium and chloride is an exams of a(n) ____ bond.
Ionic
When a concentration gradient is present, dissolved substances move from an area of ____ concentration to an area of ____ concentration. This process is called ____.
Higher
Lower
Diffusion
What is a chemical reaction?
The formation and breaking of chemical bonds.
Name three types of chemical reactions:
Synthesis
Decomposition
Exchange
The digestion of food uses which type of chemical reaction?
Decomposition
What factors influence the rate of chemical reactions?
Concentration of reactants
Temperature
Activation energy requirements
Catalysts
