A. ribose, uracil, and a phosphate group
B. deoxyribose, uracil, and a phosphate group
C. deoxyribose, thymine, and a phosphate group
D. ribose, thymine, and a phosphate group
C. deoxyribose, thymine, and a phosphate group
my answer: A change in gene sequence can lead to a different amino acid being added to a polypeptide chain instead of the normal one. This change the protein structure and function. For example, sickle cell anemia, the hemoglobin beta chain has a single amino acid substitution the amino acid glutamic acid in position six is substituted by valine. Due to change, hemoglobin molecules form aggregates, and the disc-shaped red blood cells assume a crescent moon shape, leading to health problems.
Book: A change in gene sequence can lead to a different amino acid being added to a polypeptide chain instead of the normal one. This causes a change in protein structure and function. For example, in sickle cell anemia, the hemoglobin β chain has a single amino acid substitution—the amino acid glutamic acid in position six is substituted by valine. Because of this change, hemoglobin molecules form aggregates, and the disc-shaped red blood cells assume a crescent shape, which results in serious health problems.
my answer:DNA is double stranded whereas RNA is single stranded. DNA nucleotides contains deoxyribose , one of the four nitrogenous bases [A, T, G, & C] & a phosphate group. RNA ribonucleotides contains ribose, one of the four nitrogenous bases [A, U, G, & C] & a phosphate group.
Book: DNA has a double-helix structure. The sugar and the phosphate are on the outside of the helix and the nitrogenous bases are in the interior. The monomers of DNA are nucleotides containing deoxyribose, one of the four nitrogenous bases [A, T, G and C], and a phosphate group. RNA is usually single-stranded and is made of ribonucleotides that are linked by phosphodiester linkages. A ribonucleotide contains ribose [the pentose sugar], one of the four nitrogenous bases [A,U, G, and C], and the phosphate group.
Understanding:
• Membrane proteins are diverse in terms of structure, position in the membrane and function
Phospholipid bilayers are embedded with proteins, which may be either permanently or temporarily attached to the membrane
- Integral proteins are permanently attached to the membrane and are typically transmembrane [they span across the bilayer]
- Peripheral proteins are temporarily attached by non-covalent interactions and associate with one surface of the membrane
Structure of Membrane Proteins
The amino acids of a membrane protein are localised according to polarity:
- Non-polar [hydrophobic] amino acids associate directly with the lipid bilayer
- Polar [hydrophilic] amino acids are located internally and face aqueous solutions
Transmembrane proteins typically adopt one of two tertiary structures:
- Single helices / helical bundles
- Beta barrels [common in channel proteins]
Membrane Protein Structures
Functions of Membrane Proteins
Membrane proteins can serve a variety of key functions:
- Junctions – Serve to connect and join two cells together
- Enzymes – Fixing to membranes localises metabolic pathways
- Transport – Responsible for facilitated diffusion and active transport
- Recognition – May function as markers for cellular identification
- Anchorage – Attachment points for cytoskeleton and extracellular matrix
- Transduction – Function as receptors for peptide hormones
Mnemonic: Jet Rat
Membrane Protein Functions