Chapter 2 (pt. 2: amino acids and protein) Flashcards
What are the monomers of proteins?
Amino acids.
How many different amino acids exist?
20
What are the three important functional groups attached to the central carbon atom of an amino acid?
1) Amino group (—NH2), 2) Acidic carboxyl group (—COOH), 3) Side chain (R group).
How are the amino and carboxyl groups of amino acids affected at normal body pH?
They are both ionized.
What gives each amino acid its distinctive chemical identity?
The different side chains (R groups).
What distinguishes glycine among amino acids?
It is the simplest amino acid, with a side chain that is just a hydrogen atom.
What is unique about cysteine?
It contains sulfur in its side chain and is one of only two amino acids with this element.
Describe the structure of tyrosine.
It has a side chain that contains a six-carbon aromatic ring.
What characteristic does lysine have?
It has an additional amino group at the end of its side chain, which gives it basic properties.
What are structural proteins?
Proteins that form the framework of body parts.
Give two examples of structural proteins and their locations.
Collagen (in bones and connective tissues) and keratin (in skin, hair, and nails).
What do regulatory proteins do?
They act as hormones and neurotransmitters to regulate body processes and growth.
Name two examples of regulatory proteins and their functions.
Insulin (regulates blood glucose) and Substance P (mediates pain).
What is the function of contractile proteins?
They enable muscle contraction and movement.
Give two examples of contractile proteins.
Myosin and actin.
What are immunological proteins responsible for?
They help protect the body from foreign substances and pathogens.
Name two examples of immunological proteins.
Antibodies and interleukins.
What is the role of transport proteins?
They carry essential substances throughout the body.
Provide an example of a transport protein.
Hemoglobin (transports oxygen and carbon dioxide).
What are catalytic proteins also known as?
Enzymes
Name two examples of catalytic proteins.
Salivary amylase and sucrase.
How are proteins synthesized?
By sequentially joining amino acids through peptide bonds.
Describe how a peptide bond is formed.
A covalent bond forms between the carbon in the carboxyl group of one amino acid and the nitrogen in the amino group of another, releasing a molecule of water (dehydration synthesis).
What is the process of breaking a peptide bond called?
Hydrolysis reaction, as seen during protein digestion.
What are essential (indispensable) amino acids?
Amino acids that cannot be synthesized by the human body in sufficient amounts and must be included in the diet.
Why are essential amino acids important?
necessary for various bodily functions and must come from dietary sources.
What are nonessential (dispensable) amino acids?
Amino acids that can be synthesized by the human body in sufficient amounts to meet its needs.
What is leucine and where can it be found?
Leucine is an essential amino acid found in dairy products that the body cannot synthesize on its own.
Can nonessential amino acids be obtained from the diet?
Yes, while the body can synthesize them, they can also be obtained through dietary sources.
Why is it important to consume essential amino acids?
They are necessary for building muscle and various bodily functions.
What is the benefit of consuming nonessential amino acids?
While the body can synthesize them, consuming them can still contribute to overall amino acid intake.
Which amino acid is most essential for muscle protein synthesis?
Leucine
Should branch-chain amino acids be a focus in supplementation?
While not as beneficial for some goals, prioritizing essential amino acids like leucine for muscle building is important.
How many essential amino acids are there?
9 essential amino acids.
How many non-essential amino acids are there?
11 non-essential amino acids.
What are conditionally essential amino acids?
Amino acids that can be produced by the body but are better obtained through diet during certain conditions.
How many conditionally essential amino acids are there?
3 conditionally essential amino acids.
Why might conditionally essential amino acids be important to consume?
During times of stress, illness, or recovery, the body’s demand may exceed its ability to produce them.
what does each amino acid contain?
Each amino acid contains a central carbon atom bound to a hydrogen atom, an amino group, an acid group, and a side chain.
what is the amino acid pool?
All of the amino acids in body tissues and fluids that are available for use by the body.
what is protein turnover?
The continuous synthesis and breakdown of body proteins.
What is the amino acid pool used for?
The amino acid pool is used to synthesize protein and non-protein molecules.
Where does the amino acid pool come from?
The amino acid pool comes from dietary proteins and the breakdown of existing body proteins.
How can amino acids be utilized for energy?
Amino acids can be broken down for energy.
Besides energy, what else can amino acids be used to synthesize?
Amino acids can be used to synthesize glucose or fatty acids.
What non-protein molecules can be synthesized from amino acids?
Amino acids can be used to synthesize non-protein molecules such as DNA or RNA.
Can the body store amino acids like glucose or fatty acids?
No, the body cannot store amino acids like glucose or fatty acids; they can only be stored as body proteins, which are continuously broken down and used.
function of protein in the body:
Proteins give structure to the body, regulate processes, provide protection, assist in muscle contraction, transport substances, and serve as enzymes
What is a peptide bond?
A peptide bond is a chemical bond that links amino acids together.
How is a peptide bond formed?
A peptide bond is formed between the acid group of one amino acid and the nitrogen group of the next amino acid.
What is a dipeptide bond?
A dipeptide bond is a bond formed between two amino acids.
What is a polypeptide?
A polypeptide is a chain formed from many amino acids (10 or more).
What is a protein made of?
A protein is made of one or more polypeptide chains folded into a three-dimensional shape, which determines its function.
How is a dipeptide formed?
A dipeptide is formed when two amino acids combine.
What happens when more amino acids are added to a dipeptide?
Adding more amino acids creates tripeptides, chain-like peptides (4–9 amino acids), or polypeptides (10–2000+ amino acids).
What is the structure of a small protein?
Small proteins consist of a single polypeptide chain with a minimum of 50 amino acids.
What is the structure of larger proteins?
Larger proteins can have hundreds or thousands of amino acids and may comprise multiple folded polypeptide chains.
How does the variation in amino acid number or sequence affect proteins?
Each variation in the number or sequence of amino acids results in a different protein.
How are amino acids similar to alphabet letters?
Amino acids are like alphabet letters, and their combinations create diverse peptides, polypeptides, and proteins.
What is the primary structure of a protein?
The primary structure is the linear sequence of amino acids in a protein, linked by covalent peptide bonds. This sequence is genetically determined.
What can happen if the primary structure of a protein is altered?
Alterations in the primary structure can affect the protein’s function, as seen in sickle cell disease, where a mutation changes hemoglobin’s structure, causing blood cells to deform.
What is a covalent peptide bond?
A covalent peptide bond is a chemical link formed between two amino acids in a protein.
What is the secondary structure of a protein?
The secondary structure involves the local folding of the polypeptide chain into shapes like alpha helices (spiral shapes) and beta sheets (zig-zag patterns), stabilized by hydrogen bonds.
How are secondary structures like alpha helices and beta sheets held together?
They are held together by hydrogen bonds.
What is the tertiary structure of a protein?
The tertiary structure is the overall three-dimensional shape of a polypeptide, formed by interactions like hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges.
What is the quaternary structure of a protein?
The quaternary structure involves multiple polypeptide chains arranged together, held by interactions similar to those in the tertiary structure.
What are fibrous proteins and their function?
Fibrous proteins are insoluble in water, form long strands, and have structural roles (e.g., collagen, keratin).
What are globular proteins and their function?
Globular proteins are soluble in water, spherical, and perform metabolic functions (e.g., enzymes, antibodies).
What is denaturation, and how can it happen?
Denaturation is when proteins lose their functional shape due to environmental changes, such as heat (like cooking an egg), disrupting their function.
Primary Structure
This is the linear sequence of amino acids in a polypeptide chain, connected by peptide bonds.
Secondary Structure
The local folding of the polypeptide chain into alpha helices (spiral shapes) and beta sheets (zig-zag patterns), stabilized by hydrogen bonds between amino acids.
Tertiary Structure
The overall three-dimensional shape of a single polypeptide chain, formed through interactions like hydrogen bonds, ionic bonds, and disulfide bridges.
Quaternary Structure
The arrangement of two or more polypeptide chains, coming together to form a functional protein complex.
list the types of protien:
Structural: Form structural framework of various parts of body.
Regulatory: Function as hormones that regulate various physiological processes
Contractile: Allow shortening of muscle fibers (cells) which produces movement.
Immunological: Aid responses that protect body against foreign substances and invading pathogens.
Transport: Carry vital substances throughout body.
Catalytic: Act as enzymes that regulate biochemical reactions.
“Some Really Cool Iguanas Travel Constantly.”
Where does transcription occur during protein synthesis?
Transcription occurs in the nucleus.
What is produced during transcription?
Messenger RNA (mRNA) is produced during transcription.
What happens to mRNA after it is made?
The mRNA leaves the nucleus and travels to the cytoplasm, where it attaches to a ribosome.
Where does translation take place in the cell?
Translation takes place in the cytosol.
What does the ribosome do during translation?
The ribosome reads the mRNA code three nucleotides at a time (codon) and helps assemble the corresponding amino acids.
What molecule brings amino acids to the ribosome?
Transfer RNA (tRNA) brings amino acids to the ribosome.
What is a codon?
A codon is a set of three nucleotides on mRNA that corresponds to a specific amino acid.
How are amino acids linked together during translation?
Amino acids are linked together to form a polypeptide chain.
What happens to the polypeptide chain after translation?
The polypeptide chain folds to become a functional protein.
What does nitrogen balance measure?
Nitrogen balance measures the balance between the amount of nitrogen you consume and the amount your body gets rid of.
How do you get nitrogen into your body?
You get nitrogen mostly from the protein in the food you eat.
How does your body lose nitrogen?
Your body loses nitrogen through urine, feces, sweat, and other bodily processes.
What is positive nitrogen balance?
Positive nitrogen balance occurs when you take in more nitrogen than you lose, indicating your body is building more proteins than it is breaking down.
When is positive nitrogen balance commonly seen?
Positive nitrogen balance is common during periods of growth, such as in children, pregnant women, or bodybuilders building muscle.
What is negative nitrogen balance?
Negative nitrogen balance happens when your body loses more nitrogen than it consumes, suggesting your body is breaking down more protein than it is building.
When might negative nitrogen balance occur?
Negative nitrogen balance can occur during illness, malnutrition, or periods of stress.
What is balanced nitrogen?
Balanced nitrogen occurs when nitrogen intake equals nitrogen loss, indicating a stable state.
When is balanced nitrogen typically desired?
Balanced nitrogen is typically desired for maintaining overall health in adults who are not growing or recovering from illness.
what does DNA form and regulate?
D N A forms the genetic code in the nuclei of body cells and it regulates most of the cell’s activities.
what does RNA guide?
protein formation
What elements do nucleic acids contain?
Carbon, hydrogen, oxygen, nitrogen, and phosphorus.
What are the two types of nucleic acids?
DNA (Deoxyribonucleic acid) and RNA (Ribonucleic acid).
What is the role of DNA in cells?
DNA is the genetic material that determines inherited traits and controls protein production, passing on genetic information during cell division.
How does RNA function in relation to DNA?
RNA carries instructions from DNA to guide cells in making proteins from amino acids.
What happens to DNA when cells divide?
DNA passes on genetic information to the new cells.
Why is protein production important in cells?
Proteins help regulate what happens in body cells.
What are the repeating units that make up nucleic acids?
Nucleotides
What are the three components of each nucleotide in DNA?
A nitrogenous base, a pentose sugar, and a phosphate group.
Name the four nitrogenous bases found in DNA.
Adenine (A), Guanine (G), Thymine (T), and Cytosine (C).
Which nitrogenous bases in DNA are purines?
Adenine (A) and Guanine (G).
Which nitrogenous bases in DNA are pyrimidines?
Thymine (T) and Cytosine (C).
What sugar is found in the nucleotides of DNA?
Deoxyribose, a five-carbon sugar.
What role do phosphate groups play in the structure of DNA?
They form the “backbone” of the DNA strand by linking with pentose sugars.
How do the bases A, T, C, and G contribute to the structure of DNA?
They pair up to hold the DNA strands together.
Describe the “backbone” of a DNA strand.
It is composed of alternating pentose sugars and phosphate groups
What is the structure of a DNA molecule?
DNA is arranged in a double helix.
What stabilizes the structure of the DNA helix?
Hydrogen bonds between each base pair stabilize the helix.
What is the function of DNA in human cells?
DNA forms the inherited genetic material inside each human cell.
Who proposed the structure of DNA and when?
F.H.C. Crick and J.D. Watson in 1953.
What does the double helix model of DNA resemble?
A spiral ladder.
What does the double helix model of DNA resemble?
A spiral ladder.
What forms the sides of the DNA ladder?
Alternating phosphate groups and deoxyribose sugars.
What forms the rungs of the DNA ladder?
Paired bases bonded by hydrogen bonds.
Which bases pair together in DNA?
Adenine pairs with thymine, and cytosine pairs with guanine.
What is complementary base pairing?
Knowing the sequence of one DNA strand allows prediction of the complementary strand.
What happens during DNA replication?
DNA strands unwind, and each serves as a template for a new complementary strand.
What are mutations?
Changes in the DNA sequence.
What can mutations lead to?
They can lead to cell death, cancer, or genetic defects.
What is the key structural difference between RNA and DNA in humans?
RNA is single-stranded, while DNA is double-stranded.
What type of sugar is found in RNA?
Ribose.
Which base does RNA contain that DNA does not?
Uracil (U) instead of thymine (T).
What is the primary function of messenger RNA (mRNA)?
It carries genetic instructions from DNA.
What role does ribosomal RNA (rRNA) play in cells?
It forms part of the ribosome and aids in protein synthesis.
How do RNA types contribute to the process of protein synthesis?
Each type of RNA plays a part in translating DNA’s instructions into proteins.
What is the function of transfer RNA (tRNA)?
It brings amino acids to the ribosome for protein assembly.
How do you differentiate between DNA and RNA bases in terms of thymine and uracil?
DNA contains thymine (T), whereas RNA contains uracil (U).
What is the primary role of adenosine triphosphate (ATP) in living organisms?
ATP is the primary energy carrier in all living organisms.
Name one cellular process powered by ATP.
Muscle contractions.
Give another example of a cellular activity that requires ATP.
Cell division.
How does ATP contribute to movements within cells?
It provides the energy needed for intracellular movement.
What role does ATP play in cellular transportation?
It transports substances across cell membranes.
How does ATP assist in metabolism related to building larger molecules?
It provides the energy required for building larger molecules.
Describe the structural components of ATP.
ATP consists of three phosphate groups attached to adenosine, which includes adenine and the sugar ribose.
What is the primary process cells use to produce ATP?
The breakdown of glucose during cellular respiration.
What are the two phases of cellular respiration?
The anaerobic phase and the aerobic phase.
Where does the anaerobic phase occur in the cell, and does it require oxygen?
It occurs in the cytoplasm and does not require oxygen.
What is the main product of glucose breakdown during the anaerobic phase?
Pyruvic acid.
How many ATP molecules are produced per glucose molecule during the anaerobic phase?
2 ATP molecules.
In which part of the cell does the aerobic phase occur, and what does it require?
It occurs in the mitochondria and requires oxygen.
What are the end products of glucose breakdown during the aerobic phase?
Carbon dioxide and water.
How many ATP molecules are generated per glucose molecule in the aerobic phase?
30 to 32 ATP molecules.
Why is the anaerobic phase of cellular respiration considered to occur quickly?
Because it does not require oxygen.
