Know me slide 5 Flashcards

(52 cards)

1
Q

(Greek) Proteios

A

“first” or “primary”

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2
Q

Proteins account for more than half the dry mass of

most cells.

A

Proteins have critical and diverse roles throughout

the bodies of all organisms

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3
Q

A catalyst

A
is a substance that
accelerates the rate of a
chemical reaction without
affecting the products of the
reaction and without itself
being altered or consumed by
the reaction.
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4
Q

enzymes.

A

The catalysts in living
organisms are proteins called
enzymes.

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5
Q

Enzymes are typically very large molecules that

A

bring
together or break apart substrates (the molecules upon
which a chemical reaction occurs).

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6
Q
1 Substrates enter active site; enzyme
changes shape such that its active site
enfolds the substrates (induced fit).
2 Substrates held in
active site by weak
interactions, such as
hydrogen bonds, and
ionic bonds.
3 Active site can lower the
energy needed to start
a reaction.
A
4 Substrates are
converted to
products
5 Products are
released.
6 Active
site is
available
for two new
substrate
molecules
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7
Q

Amino acids

A

are the
monomer building blocks of
proteins.

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8
Q

Polypeptides

A

are polymers

of amino acids

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9
Q

A protein consists

A

of one or

more polypeptides.

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10
Q

There are 20
different amino
acid monomers

A

from which
polypeptides are
assembled.

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11
Q

Amino Acid Monomers

A

Differ in their properties
due to differing side
chains, called R-groups

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12
Q

Amino acids are linked

by

A

peptide bonds

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13
Q

Peptide bonds are

formed

A

through

dehydration reactions

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14
Q

A protein’s specific

conformation

A

(or 3D
shape) determines its
function

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15
Q

4 Levels in Protein Structure

A
  1. Primary Structure
  2. Secondary Structure
  3. Tertiary Structure
  4. Quaternary Structure
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16
Q

Primary Structure

A

• The linked series of amino acids with a unique sequence
• The 20 amino acids can be assembled in 20^127 sequences
(for the polypeptide of 127 amino acids shown above).
• Primary structure dictates structure at higher levels

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17
Q

Secondary Structure

A

Hydrogen bonds between amino acids of a single
polypeptide (α helix) or amino acids of adjacent polypeptides
(β sheet) bring about secondary structure

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18
Q

Tertiary Structure

A
Results from interactions
between the side chains
(R-groups) of amino acids
Involves a variety of
bonds: disulfide bridges,
hydrogen bonds, van der
Waals interactions, ionic
bonds
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19
Q

Quaternary Structure

A

• The overall structures of
proteins that are comprised
of more than one
polypeptide subunits

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20
Q

Hemoglobin is the ironcontaining
oxygen transport
protein in the blood of
mammals and other animals.

A

It consists of four polypeptide
chains, each of which has a
heme group

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21
Q

Anemia –

A

decreased
hemoglobin in blood, usually
from iron deficiency

22
Q

Sickle-cell hemoglobin differs from normal hemoglobin in only
one amino acid.

A

Sickle hemoglobin molecules adhere when
they are deoxygenated, and can cause blood cells to lodge in
blood vessels.

23
Q

Denaturation

A

occurs when a protein unravels and loses its

three dimensional conformation

24
Q

The protein conformation that arises from a given primary

structure depends

A

on the physical and chemical conditions

of the protein’s environment.

25
Protein Functions
* Enzymes * Structural proteins * Storage proteins * Transport proteins * Hormones * Receptor proteins * Contractile and motor proteins * Defensive proteins
26
Collagen
is the most abundant protein in animals and provides the high tensile strength and resilience needed in skin, tendons, and ligaments
27
The venoms of stingrays and other animals are proteins.
These can act by breaking down tissues or acting on components of the nervous system.
28
Nucleic acids
are the molecules in which | hereditary information is stored and transmitted.
29
Genes
are made of nucleic acids
30
Genes are the units of inheritance
Genes specify the amino acid sequences of | polypeptides
31
Genes are the units of inheritance
Genes specify the amino acid sequences of | polypeptides
32
There are two types of nucleic acids:
-Deoxyribonucleic Acid (DNA) | – Ribonucleic Acid (RNA)
33
Both are present in cells
DNA contains the genetic “blueprint” of an organism – RNA is involved in protein synthesis
34
Nucleic acids exist as polymers called polynucleotides
made up of monomers called nucleotides
35
nucleotides
Each polynucleotide consists of monomers called nucleotides
36
Each nucleotide is made | up of a
nucleoside (a nitrogenous base and a pentose sugar) and a phosphate group
37
Nitrogenous Bases
``` 3 pyrimidines – single 6- membered ring • 2 purines – one 6- membered ring + one 5- membered ring • Differ in functional groups • Are abbreviated C, T, U, A, and G • T is found only in DNA, U is found only in RNA ```
38
DNA nucleotides contain
a deoxyribose sugar
39
RNA nucleotides contain
a ribose sugar.
40
Deoxyribose is identical to ribose except
it is missing an oxygen on the second carbon
41
Carbons of the pentose sugars
are numbered clockwise from the carbon attached to the nitrogenous base.
42
The sugar carbons are labeled with a | prime (‘)
to distinguish them from the | nitrogenous base carbons
43
phosphodiester linkages
Nucleotides are linked into polynucleotides by phosphodiester linkages
44
Polynucleotides have a 5´ end (phosphate group) and a 3´ end (hydroxyl group).
DNA molecules have directionality - has important implications for the biological roles of DNA and RNA.
45
A DNA molecule consists of two
“antiparallel” nucleotide strands (running in opposite directions One strand runs 5’ to 3’, the other runs 3’ to 5’
46
DNA
contains A, C, G, T; usually doublestranded, | has a deoxyribose pentose sugar
47
RNA
contains A, C, G, U; usually singlestranded, | has a ribose pentose sugar
48
DNA in the cell nucleus contains the instructions for protein synthesis.
Every three nucleotides | codes for an amino acid.
49
messenger RNA
``` The code is exported from the nucleus in the form of an RNA copy called messenger RNA (mRNA). ```
50
Ribosomes translate
mRNA to proteins.
51
The nucleotide sequence of the DNA molecule comprises
discrete units of inheritance called genes that specify functional proteins
52
Individual genes can be | from
100’s to 1000’s of | nucleotides long.