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Flashcards in Cell Biology Deck (136)
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1

What is the cell theory?

• Cells are the smallest independent units of life
• All living things are made up of cells
• Cells are formed by the reproduction of existing cells

2

Life on earth is what?

Carbon-based

3

What is an element?

A chemically pure substance that cannot be broken down

4

What are covalent bonds?

When electron pairs are shared, very strong

5

What is a valence shell?

The outer layer of the atom

6

What is electronegativity?

The attractive force that an atom exerts on electrons

7

How do ionic bonds form?

By chemical attraction of opposite charges
- The more electronegative atom steals an electron

8

What kind of bond does solid, water, liquid, and gas have?

Hydrogen bonds (sharing of an H atom)

9

Polar molecules are:

Hydrophilic (water-loving)

10

Non-polar molecules are:

Hydrophobic (water-hating)

11

What is hydrophilic interaction?

Attraction, polar to polar

12

What is hydrophobic interaction?

Attraction, non-polar to non-polar

13

What ions do acids release?

H+

14

What ions do bases release and accept?

Accepts H+ and releases OH-

15

What is carbon?

A “tinkertoy” atom
- Incredibly flexible- used to build many types of complex macro molecules

16

What is a common theme between living systems?

Many are biological polymers with repeated subunits

17

What is a polymer?

A repeating unit (more than two)

18

What are carbohydrates?

A source of energy
- Basic unit: CH2O
- Ex: glucose (disaccharides)

19

What are polysaccharides?

Form rigid biological structures (ex: cellulose + chitin)

20

What are the 3 classes of amino acids?

Electrically charged, polar, non-polar

21

What is the shape of a protein?

A folded polypeptide

22

What is the structure of a non-polar amino acid?

Amino acids have a hydrocarbon side-chain (ex: CH3)

23

What is the structure of a polar amino acid?

Amino acids have side chains with partial charge (polar uncharged), or net (+) charge, or net (-) charge

24

What are lipids?

Fats, steroids, phospholipids

25

What is fat?

Simple 3-carbon lipid
- Fatty acid tails, hydrophobic

26

What is a phospholipid?

2 fatty acid tails (hydrophobic) and charged phosphate head (hydrophilic)

27

What is a steroid?

Composed of carbon rings (5 or 6 carbons per ring)
- Cholesterol, estrogen, testosterone (hormones)
- Cell membranes (animals only)

28

What are the 4 bases of nucleic acids?

A (adenine), G (guanine) --- Purines
T (thymine), C (cytosine) --- Pyrimidines

29

What are the subunits of a nucleotide?

1 of 4 bases + a phosphate + a sugar

30

What is DNA?

A double helix (two strands linked together that are identical)
- bonded by hydrogen bonds