W1L3 - DNA, proteins, cells, membranes, viruses

Question 1

What is Life’s program made out of

Answer 1

Nucleci Acids

• DNA
• RNA
  
  • Long string of bases (3-3.5 billion).
  • Different orders lead to different functions.

Question 2

How is DNA structured

Answer 2

• Two strands of sugar phosphate backbone are wound in the shape of a double helix
• Strands are linked with four bases (ATGC)
  
  • A-T
  • G-C

Question 3

How is DNA replicated? (4)

Answer 3

1. DNA double helix
2. Strands separate
3. Each strand serve as template for new complementary strand (Other bases, floating in cell, come in and attach according to pair rules)
4. Two identical daughter DNA molecules

Question 4

What does DNA contain instructions for? (1)

How does it get there? (3)

Answer 4

Proteins

1. DNA, at nucleus > Transcription (RNA synthesis) >
2. mRNA (Single-stranded) > Translation (protein synthesis) >
3. Ribosome, at cytoplasm (Reads information) > Protein

Question 5

What is the DNA Language?

Answer 5

• DNA language has four letters (ATGC) which can be combined into 64 possible three letter words (e.g., ATT = F, GCC = L)

Question 6

What is the protein language

Answer 6

Protein language has 20 letters (F, L, etc) and infinite number of words of any length

Question 7

What dictates the shape and function of proteins

How many do humans, plants, bacterias have

What kind of task does protein have?

Answer 7

• The gene sequence dictates the shape and the function of each protein
  
  • Humans: 30,000 genes/proteins
  • Plants: 35,000
  • Bacteria: 5,000-9,000
• Each protein (hardware) has a very specific task in the cell

Question 8

What is innovation/improvisation? (=)

Answer 8

• Innovation = Mutations = Changes in DNA Sequence = Modification of program code
• Different proteins (different hardware) = Different fitness

Question 9

What are some ways mutations can be induced

Answer 9

• Mistakes during DNA replication
• Damage (radiation, chemical)

Question 10

What are the 2 key mutations

Answer 10

1. Substitution

• Largely neutral (Protein works, may be slightly better/worse fitness)
• Change of DNA sequence

2. Frameshift

• Negative (Protein make no sense)
• Loss or gain of DNA

Question 11

What is Schwann’s definition of cells

Answer 11

Living things are comprised of compartments (cells)

• Cell - a closed domain where the chemical reactions required for life are carried out.

Question 12

What are the tenets of cell theory (4)

Answer 12

• All known living things are made up of one or more cells.
• All living cells arise from pre-existing cells by division.
• The cell is the fundamental unit of structure and function in all living organisms.
• Cells contain hereditary information (DNA) which is passed from cell to cell during cell division.

Question 13

Who was the first person who saw cells

Answer 13

Robert Hooke invented the first microscopes and Leeuwenhoek observed microorganisms (animalcules)

TLDR: Microscopy allows us to see cells (~1 μm to 100 μm)

Question 14

All cells are enclosed by a ____.

How is it structured? (3)

Answer 14

• All membranes composed of two layers of phospholipids
• Phospholipids are schizoid (amphiphilic) molecules with opposite chemical properties at each end
  
  • Phosphate head is Hydrophilic (loves water)
  • 2 Acyl tails is Hydrophobic (hates water)
• Arranged such that water on the outside is separated from the water on the inside, and things cannot cross the membrane freely

Question 15

How do membranes react in watery environment

Answer 15

Acyl tails (Hydrophobic) faces each other

Phosphate head (Hydrophilic) faces outside

Question 16

What is a virus? (4)

Answer 16

• Infectious agent
• Not cellular, no ribosomes, no organelles
• Cannot reproduce by itself (Need a host)
  
  • Lack of the R in PICERAS
• Comprises genome (RNA or DNA), capsid (protein), and sometimes a membrane (lipid)