Biomolecules and Cell Physiology
Unsaturated fatty acids have _____ double bonds in their long hydrocarbon chains.
1 or more
There are two types of nucleic acids:
1. Deoxyribonucleic acid (DNA) 2. Ribonucleic acid (RNA)
All cells have some common structures and functions • Human cells have three basic parts:
1. Plasma membrane = Flexible outer boundary 2. Cytoplasm = intracellular fluid containing organelles 3. Nucleus = control center that contains DNA
cell theory
1. The cell is the smallest structural and functional living unit 2. Organismal functions depend on individual and collective cell functions 3. Biochemical activities of cells are dictated by their specific subcellular structures 4. Continuity of life has a cellular basis
Amino acids contain
2 functional groups: an amino group (NH2) and a carboxyl group (COOH)
Collagen requires ____ chains in a superhelix
3
Proteins are generally classified according to their
3D shapes.
Proteins have _ levels of structure
4
Humans have ____ chromosomes (23 pairs), each made up of many genes
46
The N-containing base is one of
5 types
• Proteins account for _______ of the dry weight of the human body
50%
Enzymes are very specific;
; each enzyme catalyzes a certain reaction or type of reaction only.
nuclear pores
= allow necessary transport between the nucleus and the cytoplasm
nuclear envelope
= double- layered membrane which separates the nucleus from the rest of the cell
Endomembrane system =
= set of 3 organelles that work together to perform various cellular jobs -Producing -Packaging -Exporting
Denaturation
= the process of altering the shape of a protein without breaking the amide bonds that form the primary structure. High temp, acid, base, and agitation can disrupt the shape
Hydrophobic ? hydrophillic
>
The names of most enzymes end with the suffix
"-ase" like peptidase, lipase, and hydrolase.
Classes of Biomolecules
(4) carbohydrates, lipids, proteins, nucleic acids
Outer membrane and an inner membrane with many folds.
Mitochondria
The nucleotides of both DNA and RNA contain
a 5-membered ring monosaccharide, often called the sugar component
Heme=
a complex organic compound containing the Fe2+ ion (that binds oxygen) complexed with a large N-containing ring system
Endoplasmic Reticulum (ER)
a system of channels
• An enzyme contains an ____ that binds the substrate, forming an ____ complex
active site; enzyme-substrate
DNA contains the bases
adenine, guanine, cytosine, thymine
RNA contains the bases
adenine, guanine, cytosine, uracil
In DNA, the monosaccharide is the
aldopentose D-2-deoxyribose
In RNA the monosaccharide is the
aldopentose D-ribose
Hemoglobin and myoglobin = two globular proteins that are called _____________________ because they are composed of a protein unit and a nonprotein molecule
conjugated proteins
Golgi apparatus =
consists of a stack of flattened, slightly curved membrane- enclosed sacs that are responsible for sorting, modifying and shipping off products that come from the rough ER
Contractile proteins
control muscle movements
The 3D arrangement of localized regions of a protein arise
due to hydrogen bonding between the N—H group of one amide with the C═O group of another Two stable arrangements are the ⍺-helix and the β-pleated sheet
Hydrolyzable lipids are derived from
fatty acids
A __________ is the portion of the DNA molecule responsible for the synthesis of a single protein.
gene
• In the human body, they are used for bursts of energy needed during exercise in the form of
glucose
Monosaccharides
glucose, fructose, galactose (simple sugars)
Cytoskeleton =
group of fibrous proteins that provide structural support for cells Critical for cell motility, cell reproduction, and transportation of substances within the cell
• Intermediate filaments:
important in cell regions subject to mechanical stress (intermediate in diameter) 8-12 nm
The area between the two membranes of mitochondria =
intermembrane space
Fibrous proteins,
keratin and collagen give support and structure
Proteins are
large polymers of amino acids joined by peptide bonds that are responsible for a lot of the structure and function of all living cells, come from greek word proteose, of first importance
Fatty acids are carboxylic acids with
long carbon chains of 12 to 20 C atoms
The area enclosed by the inner membrane = the ____________, where energy production occurs.
matrix
Disaccharides are
molecules with two sugars 2 monosaccharides joined together sucrose, lactose, and maltose.
• Three groups of carbohydrates:
monosaccharides, disaccharides, polysaccharides
Phospholipids
the major component of cell membranes, contain a hydrophilic polar head and two hydrophobic nonpolar tails • When phospholipids are mixed with water, they assemble into a lipid bilayer • The polar heads orient on the outside to interact with polar water molecules • The nonpolar tails orient on the inside to avoid polar water molecules
Adenine (A) and guanine (G) are based on the structure of
purine
• Cytosine (C), uracil (U), and thymine (T) are all based on the structure of
pyrimidine
Protein hormones and enzymes
regulate metabolism
Rough ER: membrane dotted with _______________ (organelles that serve as the site of protein synthesis)
ribosomes
DNA molecules contain _____ nucleotides, while RNA molecules have only_____
several million nucleotides; a few thousand
The quaternary structure of a protein is the
shape adopted when 2 or more folded polypeptide chains (each with its own tertiary structure) come together into 1 protein complex
Transfer RNA (tRNA) brings
specific amino acids to the ribosomes for protein synthesis (the smallest type)
Examples of nonhydrolyzable lipids
steroids and fat-soluble vitamins, eicosanoids
The secondary structure of a protein is
the 3D arrangement of localized regions of a protein
The tertiary structure of a protein is
the 3D shape adopted by the entire peptide chain
RNA (ribonucleic acid) translates
the genetic information contained in DNA into proteins needed for all cellular function
DNA (deoxyribonucleic acid) stores
the genetic information of an organism and transmits that information from one generation to another.
Messenger RNA (mRNA) carries
the information from DNA (in the nucleus) to the ribosome.
Collagen
the most abundant protein in vertebrates and is found in connective tissues such as bone, cartilage, tendons, teeth, and blood vessels
• ⍺-Keratins
the proteins found in hair, hooves, nails, skin, and wool They are made of 2 mainly ⍺- helix chains coiled around each other in a superhelix or supercoil and are very insoluble in water • These coils wind around other coils making larger and stronger structures like hair
Ribosomal RNA (rRNA) provides
the site where polypeptides are assembled during protein synthesis in the ribosomes (most abundant)
Carbohydrates
the starches and sugars present in foods
• Nucleus =
typically the largest single organized cell component
Nucleic acids are
unbranched polymers composed of repeating monomers called nucleotides
Hydrophyllic
water loving
• Denaturation often makes globular proteins less ___
water soluble.
Examples of hydrolyzable lipids
waxes, triacylglycerols, phospholipids
B-pleated sheet=
when 2 or more peptide chains, called strands, line up side-by-side
Deoxy means
without oxygen
• Organelles of the endomembrane system:
• Endoplasmic reticulum • Golgi apparatus • Vesicles/lysosomes
Golgi apparatus has 2 distinct sides which
• One side receives products in vesicles • The other side then releases the products after they are repackaged into new vesicles
Superimposed on secondary structure..
⍺-helices and/or β-pleated sheets are folded up to form a compact globular molecule
_________________ = process of a cell digesting its own structures
Autophagy
The sugar-phosphate groups lie on the outside of the helix and the bases lie on the inside, sugar phosphate is known as the ___
Backbone
Polysaccharides
Carbohydrates that are made up of more than two monosaccharides starch, glycogen, and cellulose
Molecular formula of simple carbohydrates =
Cn(H2O)n
• Vitamin C helps stabilize the___ chains and when missing, poorly formed collagen fibers result
Collagen
The nonprotein unit in hemoglobin and myoglobin is called _____ =
Heme
There are important differences between DNA and RNA
In RNA, the monosaccharide is- ribose The thymine (T) base is not present in RNA; instead, the uracil (U) base is used. RNA is a single strand, and smaller than DNA
Biomolecules
Organic molecules found in biological systems
Carbohydrates are synthesized in green plants by ________________________, a process that uses energy from the sun to convert CO2 and water into glucose and oxygen
Photosynthesis
The ______________, called the side chain, determines the identity of the amino acid
R group
Carbohydrates = of chemical energy
Storehouse
Hydrophobic
Water fearing
The DNA model was initially proposed by
Watson and Crick in 1953
Lipids
are biomolecules that are insoluble in water -They are defined by a physical property, and not by the presence of a particular functional group • Lipids come in a wide variety of structures and have many different functions • They contain many nonpolar C—C and C—H bonds and few polar bonds resulting in their water insolubility; serve as chemical messengers in body
Fibrous Proteins
are composed of long linear polypeptide chains that are bundled together to form rods or sheets • Insoluble in water and serve structural roles
Microtubules: help maintain
asymmetric cell shapes and play a role in complex cell movements (thickest) 25 nm in diameter; made up of tubulin which is a type of protein and they make up two types of cellular apendages that are important for motion ; cilia as well as flagella
Mitochondria = membranous,
bean-shaped organelle that converts molecules (e.g. sugars) to adenosine triphosphate (ATP)
Lysosome = contains enzymes that
break down and digest unneeded cellular components, such as a damaged organelle
hydrolyzable lipids
can be converted into smaller molecules by hydrolysis = the process of using
Nonhydrolyzable lipids
cannot be cleaved into smaller molecules by aqueous hydrolysis
transport proteins
carry substances through the blood
Microfilaments: important to
cellular contractile systems and as mechanical stiffeners (thinner) 7 nm in diameter, actin is primary component to make this up
Saturated fatty acids have
no double bonds in their long hydrocarbon chains.
DNA is contained in the chromosomes of the
nucleus; each chromosome having a different type of DNA.
The primary structure of a protein is the
particular sequence of amino acids that is joined together by peptide bonds • It determines all properties and function of a protein
a-helix =
peptide chain twists into a spiral
Smooth ER = synthesizes
phospholipids and steroid hormones
DNA consists of two
polynucleotide strands that wind into a right-handed double helix. The two strands run in opposite directions; one runs from the 5ʹ end to the 3ʹ end and the other runs from the 3ʹ end to the 5ʹ end.
Enzymes =
proteins that serve as biological catalysts for reactions in all living organisms