Nutrition L22

Nutrition L22 - Chapter
14
 Nutri.on:

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Unformatted text preview: Chapter
14
 Nutri.on:

 You
Are
What
You
Eat
 Nutrients

 Nutrients
are
life‐sustaining
 Cells
of
our
body
require
nutrients
in
usable
form
 –  
 
to
maintain
homeostasis

 –  
 create
ATP
 We
cannot
manufacture
our
own
organic
compounds
 –  obtained
from
environment
 Nutrients
 Two
main
types
of
nutrients
 –  Macronutrients

 •  carbohydrates,
lipids,
and
proteins
 –  micronutrients

 •  vitamins
and
minerals
 Micronutrients
required
for
proper
funcAoning
of
 essenAal
compounds

 –  Ex.
enzymes
of
cellular
respiraAon
 Macronutrients
 Three
classes
of
macronutrients
 –  carbohydrates
 –  fats
 –  Proteins
 From
these
macronutrients,
the
body
synthesizes
cellular
 components

 –  cell
membrane,
enzymes,
organelles
 –  enArely
new
cells
during
cell
division
(mitosis
and
meiosis)
 Carbohydrates
 Carbohydrates
=
most
efficient
source
of
energy
 –  “digesAon”
of
carbohydrates
leaves
nothing
but
energy,
water,
and
 carbon
dioxide
are
leM
 –  carbohydrates
are
composed
of
carbon,
hydrogen,
and
oxygen
in
a
 1:2:1
raAo

 –  the
most
common
carbohydrate,
glucose,
has
the
chemical
 formula
C6H12O6
 Our
bodies
are
excellent
at
breaking
down
glucose
to
produce
 ATP
or
synthesize
amino
acids,
glycogen,
or
triglycerides
 Lipids
 Lipids
(fats):
 –  
 long
chains
of
carbon
molecules
 –  
 many
carbon
atoms
and
far
fewer
oxygen
atoms
than
 carbohydrates
 Saturated:

 –  every
space
in
the
carbon
chain
is
occupied
with
hydrogens
 Unsaturated:
 –  one
or
more
double
bonds
in
the
carbon
chain
 –  monounsaturated
fat
–
has
one
double
bond

 –  if
the
fat
has
more
than
one
double
bond,
it
is
 polyunsaturated
 Lipids
 Lipoproteins
 Fats
are
not
soluble
in
water
 Not
readily
transported
through
our
(“watery”)
blood
 Combine
with
protein
to
form
a
lipoprotein
 –  the
lipids
are
“coated”
with

 
proteins,
phospholipids,

 
and
cholesterol
 Proteins
 Proteins
are
an
essenAal
part
of
our
diet
because
the
 amino
acids
they
contain
are
not
stored
in
the
body
 –  instead
of
completely
breaking
down
the
amino
 acids
of
ingested
proteins
for
energy,
the
body
 usually
recycles
them
into
proteins
of
its
own

 Proteins
 Of
the
20
amino
acids
that
make
up
living
organisms,
we
can
 manufacture
only
11
 –  the
remaining
8
essenAal
amino
acids
must
come
from
 our
diet
 Complete
proteins,
such
as
those
found
in
red
meat
and
fish,
 contain
all
20
amino
acids
 –  no
single
vegetable
or
fruit
contains
all
eight
of
the
 essenAal
amino
acids
 Food
Groups
 Food
groups
are
not
nutrient
classes
 –  they
are
the
major
categories
of
foods:
meats,
dairy
 products,
breads
and
pastas,
vegetables,
and
oils
or
fat
 Each
group
is
important
to
overall
health,
and
the
 recommended
daily
caloric
intake
for
each
group
differs
 The
food
guide
pyramid
offers
guidelines
for
the
number
of
 servings
of
each
type
of
food
that
should
be
eaten
each
 day
 Food
Groups
 A
healthy
diet
must
include
vitamins
and
minerals
 Micronutrients
are
not
broken
down,
but
instead
are
used
 intact
and
are
required
for
enzyme
funcAoning
or
the
 synthesis
of
specific
proteins
 Vitamins
are
organic
substances,
such
as
thiamine,
riboflavin,
 and
vitamin
A

 –  taking
too
large
a
quanAty
of
fat‐soluble
vitamins
can
cause
them
 to
build
up
in
the
liver,
hampering
its
funcAoning
 Micronutrients
 Minerals
are
inorganic
substances
such
as
calcium,
zinc,
and
 iodine
 Metabolism
 The
nutrients
we
take
in
must
be
put
to
work
 The
term
metabolism
refers
to
the
chemical
reacAons
 in
cells
that
break
down
and
build
up
nutrients
 There
are
two
basic
kinds
of
metabolic
reacAons
 –  anabolic
reacAons
‐
combine
molecules
into
more
complex
 compounds,
consuming
more
energy
than
it
produces

 –  catabolic
reacAons
‐
break
molecules
down,
producing
 more
energy
than
it
consumes
 Carbohydrates,
lipids,
and
proteins
all
undergo
both
 anabolic
and
catabolic
reacAons
 Cellular
Respira.on
 Carbohydrate
catabolism,
or
cellular
respiraAon,
is
actually
a
 controlled
burning
of
the
glucose
molecule
through
a
series
 of
enzymaAc
reacAons
that
take
place
in
our
cells
 –  we
release
the
energy
in
foods
through
a
process
that
 involves
sequenAally
breaking
chemical
bonds
 –  carbohydrate
metabolism
releases
energy
gradually
 Cellular
 Respira.on
 •  Glycolysis
 •  Kreb’s
Cycle
 •  Electron
Transport
Chain
 Most
of
the
glucose
in
our
bodies
is
catabolized
(broken
down)
to
make
 ATP
 Many
glucose
molecules
combine
to
form
glycogen,
the
only
 carbohydrate
that
is
stored
in
our
bodies—in
the
liver
and
skeletal
 muscles
 The
hormone
insulin is
a
key
to
the
synthesis
of
glycogen,
a
process
 called
glycogenesis
 Lipids,
like
carbohydrates,
can
be
oxidized
to
produce
ATP
 If
the
body
lacks
carbohydrates
(normal
source
for
glucose)
needed
to
 produce
ATP,
fat
stores
get
converted
into
small
molecules
called
 ketones
 Ketones
are
oxidized
to
produce
ATP,
their
concentraAon
in
the
blood
 Glucose
 Lipid
Storage
 Just
as
we
can
catabolize
lipids
for
energy,
we
can
also
synthesize
 and
store
them
 When
we
consume
more
calories
than
are
needed
to
meet
our
 ATP
needs,
the
body
converts
excess
glucose
into
lipids
called
 triglycerides
 –  these
are
commonly
stored
in
our
fat
cells,
also
called
 adipose cells
 •  the
result—
fat
deposits
 Energy
input
should
match
energy
output
 When
the
amount
of
energy
provided
by
all
the
nutrients
 taken
in
by
the
body
matches
the
amount
of
energy
it
 expends,
body
weight
remains
constant

 This
is
known
as
energy homeostasis
 When
the
two
amounts
don’t
match,
we
either
gain
or
lose
 weight

 We
know
that
the
amount
of
energy
coming
into
our
bodies
is
 directly
related
to
the
food
we
eat
 Energy
 Energy
 ...
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