Midterm 1: Lec 2 Slides

Question 1

What did the Miller & Urey experiment prove?

Answer 1

Organic molecules can be made from inorganic molecules (especially under conditions similar to those of primitive Earth)

Question 2

What is the “RNA World” hypothesis?

Answer 2

RNA existed before DNA- and protein-based life; DNA probably evolved from RNA and became the primary molecule for info storage

Question 3

Hierarchical organization of life(?)

Answer 3

Atoms, molecules, organelles, cells, tissues, organs, organ system, organism (in ascending order)

Question 4

Tissue

Answer 4

Group of similar cells that carry out a particular function in an organism

Question 5

4 tissue types

Answer 5

Epithelial (forms boundaries), connective, nervous (brain, nerves), muscle

Question 6

Organ

Answer 6

Structure composed of more than one tissue type (e.g., skin is epithelial cells over connective tissue)

Question 7

Types of muscle tissue

Answer 7

Skeletal, cardiac, smooth

Question 8

What are the characteristics of living things (5)?

Answer 8

• Cellular organization
• Sensitivity (response to stimuli)
• Growth (energy released by interconverting molecules is used to grow)
• Reproduction
• Homeostasis (maintain relatively constant internal conditions)

Question 9

What is the difference between anabolism and catabolism?

Answer 9

Anabolism is complex molecule from simpler one (building); catabolism is complex molecule broken down into simpler one

Question 10

Virus structure

Answer 10

Nucleic acid core surrounded by protein sheath (sometimes a lipid envelope)

Question 11

Why are viruses not considered organisms (and therefore alive)?

Answer 11

• No cell membranes, nucleus, or organelles
• Cannot reproduce alone (need host cell)
• Don’t carry out metabolism

Question 12

Cell theory principles (3)

Answer 12

• All organisms made of cells
• Cell is basic building block of life (chemical reactions of life take place in cells)
• All cells arise by division of pre-existing cell

Question 13

Why are cells small?

Answer 13

Need to have large surface area-to-volume ratio to function (if cell too large, not enough material will be able to enter to accommodate large volume)

Question 14

What do cells need to do to survive?

Answer 14

• Obtain and process energy
• Convert genetic info of DNA into protein
• Allow biochemical reactions to occur

Question 15

Where is DNA in prokaryotic cells?

Answer 15

Coiled in a nucleoid region, which is in direct contact with cytoplasm (prokaryotes can have more than one)

Question 16

Which types of organisms are prokaryotes and which are eukaryotes?

Answer 16

Eukaryotes: plants, animals, fungi, protists
Prokaryotes: Eubacteria and Archaebacteria

Question 17

Which bacteria carry out photosynthesis?

Answer 17

Cyanobacteria

Question 18

How do flagella move and what are they made of?

Answer 18

Complex protein ring structures anchored in plasma membrane form a motor unit that rotates the flagellum and propels cell - made of flagellin (protein)