Ch. 2 - Chemical Level of Organization Flashcards

1
Q

In an atom, the number of protons is ______ to the number of electrons

A

equal

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2
Q

What is the difference between the atomic number and mass number of an atom?

A

ATOMIC - number of protons (electrons too in an atom) in nucleus
MASS - sum of protons and neutrons in nucleus

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3
Q

What is a radioactive isotope?

A

Decay of nucleus gives off particles and energy; can cause DNA mutations

*difference in number of neutrons

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4
Q

What is the valence of an element?

A

The number of electrons necessary to complete outer shell; corresponds to # of cov bonds an element can form

if shell is not filled: chemically reactive!
if shell is full: chemically inert (e.g. noble glasses)

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5
Q

What is the difference between a compound and a molecule?

A

Compound: substance containing 2 or more different elements; can be broken in to diff types of atoms

Molecule: 2 or more atoms sharing e; involve covalent bonds

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6
Q

4 Properties of Water

A

*H-bonds give rise to such properties!!

  1. Highly cohesive; creates surface tension
  2. High heat capacity
  3. Expands upon freezing
  4. Versatile solvent - due to polarity
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7
Q

What are buffers?

A

Accept [H+] if too much or donate H+ if not enough in a solution; maintain pH at constant (not always neutral!) level

e.g. H2CO3 (carbonic aid) breaks down into HCO3 + H+

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8
Q

Catabolic pathways…

A

…release energy (exergonic) by breaking down complex molecules into simpler compounds

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9
Q

Anabolic pathways…

A

—require energy (endergonic) to build complex molecules from simple ones

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10
Q

How do enzymes function in chemical reactions?

A

Enzymes act as catalysts to speed up rxn rate by lowering activation energy

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11
Q

Difference between dehydration synthesis and hydrolysis?

A

Dehydration - links monomers into polymers by removing water

Hydrolysis - breaks down polymers into monomers by adding water

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12
Q

Function and properties of carbohydrates?

A
  • Cn H2n On structure
  • many -OH groups
  • provide energy to cells
  • polar covalent bonds, hydrophilic
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13
Q

C/C glycogen, starch, and cellulose

A
  • All made up of glucose monomers

Glycogen - energy storage of animals
Starch - energy storage of plants, less compact/unbranched
Cellulose - structural polysaccharide in plants; linked differently

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14
Q

Why are lipids hydrophobic?

A

Made of nonpolar, hydrophobic molecules (usually hydrocarbons which are not made via dehydration synthesis)

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15
Q

3 important types of lipids

A

Triglyceride, phospholipids, steroids

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16
Q

Composition and function of a triglyceride?

A

Made of glycerol and 3 fatty acids; energy storage

  • identity depends on type of F.A. it contains (differ in # of C, amount and position of double bonds)
17
Q

Saturated vs. Unsaturated FA

A

S - no double bonds (straight chain), solid/dense at room temp; derived from animals

US - one or more double bonds (causes kinks), liquid at room temp; derived from plants

18
Q

Cis vs. Trans Unsaturated FA

A

CIS - found in nature; liquid at room temp.

TRANS - mimic sat. FA (straight structure/pack well), processed

19
Q

Properties of Phospholipids

A
  • similar to fats, but replace 1 FA with a phosphate group
  • amphipathic
  • forms bilayers; basis of cellular membranes!
20
Q

Properties of steroids

A
  • lipids with carbon skeletons bent to form 4 fused rings
  • all made from cholesterol as starting molec

e.g. hormones (estrogen, cortisol), vitamins

21
Q

Functions of proteins?

A

give structure, regulate processes, provide protection, transport substances, act as substances

22
Q

What are amino acids?

A
  • Monomers of proteins
  • all have amino base, carboxyl acid group, hydrogen
  • differ by side chains (R groups)
23
Q

What are the 4 levels of protein structure?

A

Primary - linear
Secondary - alpha helix and beta pleated sheets
Tertiary - 3D shape formed via R group interactions
Quaternary - multiple polypeptides

24
Q

What causes denaturation?

A

Changes in pH, temperature, salt concentration, and other env factors

  • causes loss in protein’s native structure; biologically inactive
25
Q

Describe enzyme specificity

A

Due to enzyme shape (lock and key); shape of substrate and active site are complementary

26
Q

What are nucleotides? Discuss structure.

A
  • Monomers of nucleic acids

- all have P group, pentose sugar, and nitrogenous base

27
Q

Compare and contrast pyrimidines and purines

A
  • all nitrogenous bases

PYRIMIDINE - 1 ring; C, T, U

PURINE - 2 rings: A, G

28
Q

How are the 2 strands in DNA held together?

A

via H-bonds, create double helix

29
Q

What are the 3 types of RNA?

A

transfer RNA
ribosomal RNA
messenger RNA

30
Q

How does ATP power cellular work?

A

via phosphorylation

  • when hydrolyzed into ADP + P, energy is released