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 are the main functions of the cell membrane?

  • Controls movement of substances in and out
  • Contains receptors for hormones
  • Enables adjacent cells to stick together
• What is the composition of the cell membrane?

  Phospholipid bilayer with embedded proteins
• What does the fluid mosaic model describe?

  The structure and fluidity of the cell membrane
• 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 the cell membrane?

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

  Passive movement of small, non-polar molecules
• How does the rate of gas exchange by diffusion increase?

  By increasing surface area, decreasing 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 energy source is required for active transport?

  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 is the pairing 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 pairing of mRNA bases?

  A-U and C-G
• What sugar is found in mRNA?

  Ribose
• What are the stages of protein synthesis?

  1. Transcription in the nucleus
  2. Translation at the ribosomes
• What is the structure of tRNA?

  Single-stranded, folded into a specific pattern

  
• What happens during transcription?

  DNA is transcribed into mRNA

  
• What is the role of tRNA in protein synthesis?

  It carries anticodons complementary to mRNA codons

  
• What is the role of RNA polymerase in transcription?

  It catalyzes the formation of mRNA
• What occurs after mRNA is formed?

  It moves out of the nucleus to ribosomes
• What happens during translation?

  Amino acids join to form a polypeptide chain
• What is a gene?

  A series of bases coding for amino acids
• What is the genetic code?

  Order of bases coding for amino acids
• What do triplets of bases code for?

  Particular amino acids in a polypeptide chain
• What is the relationship between genes and polypeptide chains?

  Genes code for sequences of amino acids
• Do all parts of the genome code for proteins?

  No, some sections are non-coding
• What happens to tRNA molecules after they detach from amino acids?

  They are released from the amino acids.

  
• What leads to the formation of a polypeptide chain?

  The repeated process until a stop codon is reached.