Genes & health

• What increases the rate of gas exchange by diffusion?

  Increased surface area, decreased diffusion distance
• What does Fick's Law state about diffusion?

  Larger surface area and concentration difference increase rate
• How are mammal lungs adapted for gas exchange?

  Large surface area, good blood supply, short diffusion distance
• Why is a good blood supply important for lungs?

  It maintains a steep concentration gradient
• What is the thickness of alveoli in mammal lungs?

  One cell thick
• What is the composition of cell membranes?

  Phospholipid bilayer with embedded proteins
• What are the types of membrane proteins?

  Transport, receptor, enzyme, structural, recognition
• What is the main function of the cell membrane?

  Control movement of substances in and out
• What model describes the structure of the cell membrane?

  Fluid mosaic model
• What factors affect the movement of molecules through the cell membrane?

  Properties of the molecule and cell requirements
• What are the types of movement through cell membranes?

  • Diffusion
  • Facilitated diffusion
  • Osmosis
  • Active transport
  • Endocytosis/Exocytosis
• What is diffusion?

  Passive movement of small, non-polar molecules
• What increases the rate of gas exchange by diffusion?

  Increased surface area, decreased diffusion distance
• What is facilitated diffusion?

  Transport of polar molecules via channel proteins
• What is osmosis?

  Movement of water from low to high solute concentration
• What is active transport?

  Transport against concentration gradient using energy
• What is required for active transport?

  Energy in the form of ATP
• What is endocytosis?

  Transport of large particles into the cell
• What is exocytosis?

  Transport of large particles out of the cell
• What are the bases in a mononucleotide?

  Adenine, guanine, cytosine, thymine
• What are the pairings of DNA bases?

  A-T and C-G
• What sugar is found in DNA?

  Deoxyribose
• What bonds hold the DNA structure together?

  Phosphodiester and hydrogen bonds
• What is the structure of DNA?

  Double-stranded alpha double helix
• What are the bases in mRNA?

  Adenine, guanine, cytosine, uracil
• What is the structure of mRNA?

  Single-stranded, carries codons
• What is the role of tRNA?

  Carries anticodons complementary to mRNA

  
• What are the stages of protein synthesis?

  Transcription and translation
• Where does transcription occur?

  In the nucleus
• What happens during transcription?

  DNA is transcribed into mRNA

  
• What is the role of RNA polymerase in transcription?

  Catalyzes the formation of mRNA
• What happens to mRNA after transcription?

  Moves out of the nucleus to ribosomes
• What occurs during translation?

  Amino acids join to form a polypeptide chain
• What is the genetic code?

  Order of bases coding for amino acids
• What is a gene?

  Series of bases coding for amino acids
• What is the significance of triplets in the genetic code?

  Each triplet codes for a specific amino acid
• What happens to amino acids during protein synthesis?

  They are joined by peptide bonds
• What is the role of non-coding sections of DNA?

  They do not code for proteins
• What do tRNA molecules detach from?

  Amino acids
• What is formed when tRNA molecules detach from amino acids?

  A polypeptide chain