BIO201 – Anatomy and Physiology I - PowerPoint Presentation

Slide1

BIO201 – Anatomy and Physiology IBiological Macromolecules

Kamal Gandhi

Lecture 2

Slide2

MoleculesVery few elements are functional in the body in their inert, unchanged form

Most elements, instead, are found as ions or as parts of molecules

A molecule is the result of two or more atoms being bound together

Atoms form bonds in order to complete their valence shell of electrons

Slide3

SPONCH

The 6 SPONCH elements are vital for the formation of biological macromolecules because of their chemical bonding abilities

S

P

O

N

C

H

Slide4

Table 2-1

Slide5

Biological Marcomolecules

The SPONCH elements make up the building blocks of cells – the 4 biological macromolecules

Carbohydrates: short term energy storage

Lipids: long term energy storage, membranes

Proteins: cellular workhorse (functional part of a cell)

Nucleic acids: genetic information (blueprint of a cell)

These macromolecules are long chains (polymers) built from small parts (monomers)

Slide6

Monomers and PolymersIndividual subunits are combined with each other to form large macromolecules

Water is directly involved in these reactions

Dehydration synthesis: a bond is formed by the removal of water

Hydrolysis: a bond is broken by the addition of water

Slide7

Fig. 5-2

Short polymer

HO

1

2

3

H

HO

H

Unlinked monomer

Dehydration removes a water

molecule, forming a new bond

HO

H

2

O

H

1

2

3

4

Longer polymer

(a) Dehydration reaction in the synthesis of a polymer

HO

1

2

3

4

H

H

2

O

Hydrolysis adds a water

molecule, breaking a bond

HO

H

H

HO

1

2

3

(b) Hydrolysis of a polymer

Slide8

Carbohydrates

The primary molecule used by cells to make energy is carbohydrates

Contains a [C(H

2

O)]

n

motif

They can be used immediately to make ATP, the energy molecule of a cell

They can also be stored for “medium-term” in long chains or polymers

A few carbohydrates are more stable and are used as structural molecules

Carbohydrates typically contain carbonyl groups

Slide9

Fig. 5-3

Dihydroxyacetone

Ribulose

Ketoses

Aldoses

Fructose

Glyceraldehyde

Ribose

Glucose

Galactose

Hexoses (C

6

H

12

O

6

)

Pentoses (C

5

H

10

O

5

)

Trioses (C

3

H

6

O

3)

Slide10

Carbohydrates

The scientific name of carbohydrates are “

saccharides

”

A single unit of a

saccharide

is a monosaccharide

There are three common

monosaccharides

that are a part of your diet: glucose, fructose, and

galactose

In a water environment (like a cell), these molecules will circularize into a ring structure at the carbonyl group

Slide11

Fig. 5-4a

(a) Linear and ring forms

Slide12

DissaccharidesIn nature, the three

monosaccharides

combine into disaccharides that are common parts of your diet

Maltose: glucose + glucose, a common part of starchy foods

Lactose:

galactose

+ glucose, a common part of dairy

Sucrose: glucose + fructose, aka table sugar

Slide13

Fig. 5-5

(b) Dehydration reaction in the synthesis of sucrose

Glucose

Fructose

Sucrose

Maltose

Glucose

Glucose

(a) Dehydration reaction in the synthesis of maltose

1–4

glycosidic

linkage

1–2

glycosidic

linkage

Slide14

Polysaccharides

Glucose is the primary sugar that almost all living organisms use for energy

When cells/organisms have extra glucose, they can store it for short/medium term

They do this by forming long chains of glucose – polysaccharides

In plants, longs chains of glucose are called starch

While starch is made by the plant to store glucose, starchy foods provide a large energy source in our diet

In humans/animals, long chains of glucose are called glycogen, and can be stored in the liver/muscles

Slide15

Fig. 5-6

(b) Glycogen: an animal polysaccharide

Starch

Glycogen

Amylose

Chloroplast

(a) Starch: a plant polysaccharide

Amylopectin

Mitochondria

Glycogen granules

0.5 µm

1 µm

Slide16

Structural polysaccharidesIn a few cases, chains of glucose form more stable molecules that do not break down very easily

This is done by using an alternate form of glucose

The plant cell wall is made up of cellulose, a chain of

β

-glucose

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α vs β glucose

When glucose forms it’s ring structure, the bond at C1 can form in two orientations (“up”

vs

“down”)

The version that cells use for energy is the “down” orientation –

α

glucose

Some organisms are able to make the “up” orientation as well –

β

glucose

Since most organisms do not have the enzymes needed to breakdown

β

glucose, it is used as a stable, structural molecule in plants (cellulose)

Because we cannot breakdown

β-glucose, this version passes through the body unchanged - fiber

Slide18

Fig. 5-7a

(a)

 and  glucose ring structures

 Glucose

 Glucose

Slide19

Fig. 5-7bc

(b) Starch: 1–4 linkage of

 glucose monomers

(c) Cellulose: 1–4 linkage of

 glucose monomers

Slide20

Fig. 5-8

Glucose

monomer

Cellulose

molecules

Microfibril

Cellulose

microfibrils

in a plant

cell wall

0.5 µm

10 µm

Cell walls

Slide21

Lipids

One of the most stable macromolecules are fats

Because they are so stable, fats (lipids) can be used for long-term energy storage

A second, more important function of lipids in a cell is that they are used to make cellular membranes

There are two alternate forms of lipids that are utilized for these functions – triglycerides and phospholipids

A third, minor lipid in nature, though a very important one for cells, are steroids, which are used to stabilize membranes and for hormones

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Triglycerides

The form of fat that we use for long-term energy storage (and to provide cushioning to organs, insulation to the body, etc) is a triglyceride

The “

glyceride

” part refers to the central sugar molecule, a 3-C molecule called glycerol

The “tri” part refers to the 3 fatty acids that are attached to the glycerol, one to each carbon

These fatty acids are long hydrocarbon chains that are non-polar, making fats hydrophobic so they don’t dissolve in water

Slide23

Fig. 5-11a

Fatty acid

(palmitic acid)

(a)

Dehydration reaction in the synthesis of a fat

Glycerol

Slide24

Fig. 5-11b

(b)

Fat molecule (triacylglycerol)

Ester linkage

Slide25

Fatty acids

One end of the fatty acid contains a carboxyl group, allowing it to bind to the glycerol

The hydrocarbon tail of a fatty acid can be of varying length, typically 14-, 16-, or 18-C long

The fatty acid tail is only made up of C and H; but occasionally some of the Cs form double bonds

In a saturated fat, there are no double bonds, and the fat is therefore saturated with the maximum Hs

In an unsaturated fat, there is a double bond, and so there are less than the maximum number of Hs

Slide26

Fig. 5-12a

(a)

Saturated fat

Structural

formula of a

saturated fat

molecule

Stearic acid, a

saturated fatty

acid

Slide27

Fig. 5-12b

(b)

Unsaturated fat

Structural formula

of an unsaturated

fat molecule

Oleic

acid, an

unsaturated

fatty acid

cis

double

bond causes

bending

Slide28

Fats

A saturated fat will allow the fat molecules to align closer together, making these fats solid (at room temp)

An unsaturated fatty acid will have a kink in the tail; which prevents close packing of these fats, and so they tend to be liquid (at room temp)

Unsaturated fats can be mono- (one double bond) or poly- (multiple double bonds) unsaturated

A hydrogenated fat (like margarine) is an unsaturated fat to which H has been added, causing it to lose its double bond (which can be bad for you if it happens incorrectly)

Slide29

Phospholipids

The second major class of fat molecules are

phospho

-lipids, which are used for virtually all cell membranes

In these molecules, one of the fatty acids is replaced with a phosphate group (PO

4

), which has a negative charge and is therefore hydrophilic

The

phospholipid

therefore has a hydrophilic head region (the glycerol and phosphate) and a hydrophobic tail region (the 2 remaining fatty acids)

Because it it

amphipathic

,

phospholipds

will form a bilayer structure in water (discussed more next lecture)

Slide30

Fig. 5-13ab

(b)

Space-filling model

(a)

Structural formula

Fatty acids

Choline

Phosphate

Glycerol

Hydrophobic tails

Hydrophilic head

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Fig. 5-14

Hydrophilic

head

Hydrophobic

tail

WATER

WATER

Slide32

SteroidsThe third type of lipid is a steroid molecule

In cells, steroids (sterols/cholesterols) are important for maintaining stability as temperatures change

Furthermore, in our body, steroids serve as a major class of hormone

Slide33

Fig. 5-15

Slide34

Fig. 7-5c

Cholesterol

(c) Cholesterol within the animal cell membrane

Slide35

ProteinsThe protein is the most important part of a cell, because it provides that cell with all of its functional ability

Proteins can be described as our cellular workhorse

It carries out all of the functions of a cell, including structure, movement, support, signaling, and

enzymes

Proteins are chains of amino acids, linked together by peptide bonds

The function of an individual protein is based on its structure, and the structure is based on the sequence of these amino acids

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Table 5-1

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Amino acids

There are 20 naturally occurring amino acids in nature

All amino acids share the same overall structure, with a central Carbon bound to an amino group, a carboxyl group, and a Hydrogen

The 4

th

bond of the central carbon is to a variable side group, called the R group

The chemical characteristics of the R group gives individual amino acids their different characteristics

Slide38

Fig. 5-UN1

Amino

group

Carboxyl

group

 carbon

Slide39

Fig. 5-17

Nonpolar

Glycine

(Gly or G)

Alanine

(Ala or A)

Valine

(Val or V)

Leucine

(Leu or L)

Isoleucine

(Ile or

I

)

Methionine

(Met or M)

Phenylalanine

(Phe or F)

Trypotphan

(Trp or W)

Proline

(Pro or P)

Polar

Serine

(Ser or S)

Threonine

(Thr or T)

Cysteine

(Cys or C)

Tyrosine

(Tyr or Y)

Asparagine

(Asn or N)

Glutamine

(Gln or Q)

Electrically

charged

Acidic

Basic

Aspartic acid

(Asp or D)

Glutamic acid

(Glu or E)

Lysine(Lys or K)

Arginine

(Arg or R)

Histidine(His or H)

Slide40

Peptide bonds

Amino acids are linked together by peptide bonds into long chains to make functional proteins

A peptide bond is a repeatable bond formed between the carboxyl group of one amino acid and the amino group of the next amino acid

Because this leave another free carboxyl group, another amino acid can be added downstream

As this process continues, it creates a direction to proteins; the N-terminus (front end) and C-terminus (back end)

Slide41

Peptide

bond

Fig. 5-18

Amino end

(N-terminus)

Peptide

bond

Side chains

Backbone

Carboxyl end

(C-terminus)

(a)

(b)

Slide42

PolypeptidesAs amino acids grow longer, they will start to fold into a 3-dimensional structure

This

structure determines

the

function

of the protein

We typically define 4 different levels of protein structure

Primary: the sequence of amino acids

Secondary: folding into

α

-helices and

β

-pleated sheets, caused by H-bonding of the backbone

Tertiary: folding of the polypeptide caused by interactions between side groups (disulfide bridges between

cysteine, H bonds, ionic bonds, van der Waals interactions)

Quarternary: interactions between multiple polypeptides

Slide43

Fig. 5-21a

Amino acid

subunits

+

H

3

N

Amino end

25

20

15

10

5

1

Primary Structure

Slide44

Fig. 5-21c

Secondary Structure

 pleated sheet

Examples of

amino acid

subunits

 helix

Slide45

Fig. 5-21f

Polypeptide

backbone

Hydrophobic

interactions and

van der Waals

interactions

Disulfide bridge

Ionic bond

Hydrogen

bond

Slide46

Fig. 5-21e

Tertiary Structure

Quaternary Structure

Slide47

Fig. 5-21g

Polypeptide

chain

 Chains

Heme

Iron

 Chains

Collagen

Hemoglobin

Slide48

Structure determines function

The 3D structure of a protein is vital to determining its function

Typically because the structure affects the interactions of the protein with other molecules

Protein structure can be altered by changing the chemical environment (pH) or the physical environment (temperature), causing proteins to denature (unfold)

Sometimes, changing just one amino acid can cause the protein to

misfold

, creating the wrong structure and a partially or non-functional protein

Slide49

Fig. 5-19

A ribbon model of lysozyme

(a)

(b)

A space-filling model of lysozyme

Groove

Groove

Slide50

Fig. 5-22

Primary

structure

Secondary

and tertiary

structures

Quaternary

structure

Normal

hemoglobin

(top view)

Primary

structure

Secondary

and tertiary

structures

Quaternary

structure

Function

Function

 subunit

Molecules do

not associate

with one

another; each

carries oxygen.

Red blood

cell shape

Normal red blood

cells are full of

individual

hemoglobin

moledules, each

carrying oxygen.

10 µm

Normal hemoglobin









1

2

3

4

5

6

7

Val

His

Leu

Thr

Pro

Glu

Glu

Red blood

cell shape

 subunit

Exposed

hydrophobic

region

Sickle-cell

hemoglobin





Molecules

interact with

one another and

crystallize into

a fiber; capacity

to carry oxygen

is greatly reduced.





Fibers of abnormal

hemoglobin deform

red blood cell into

sickle shape.

10 µm

Sickle-cell hemoglobin

Glu

Pro

Thr

Leu

His

Val

Val

1

2

3

4

5

6

7

Slide51

EnzymesPerhaps the most important function of proteins in a cell is to serve as a biological catalyst (enzymes)

A catalyst is a molecule that speeds up chemical reactions without being changed by the reaction

It speeds up the reaction by requiring less energy

All chemical reactions that take place in a cell require enzymes in order to occur under biological time and energy constraints

Slide52

Fig. 5-16

Enzyme

(sucrase)

Substrate

(sucrose)

Fructose

Glucose

OH

H

O

H

2

O

Slide53

Nucleic acidsNucleic acids serve as genetic information for a cell

This genetic information comes in two forms, DNA (permanent copy) and RNA (temporary copy)

They provide the information necessary to maintain and reproduce a cell

They are also passed from the mother cell to the two daughter cells during cell division; or from parent to offspring during reproduction

* Since they provide the information to make a cell function, and the functional part of a cell are the proteins, nucleic acids are a blueprint to make proteins

Slide54

Nucleic acidsThe permanent blueprint stored by a cell is DNA

The sequence of DNA is called the genome, and it contains the information to make all of the proteins the cell/organism might ever need

The code for one individual protein is called a gene

That gene gets

transcribed

into RNA, a temporary copy of the blueprint for one protein

The RNA is then

translated

into a protein

Slide55

Fig. 5-26-3

mRNA

Synthesis of

mRNA in the

nucleus

DNA

NUCLEUS

mRNA

CYTOPLASM

Movement of

mRNA into cytoplasm

via nuclear pore

Ribosome

Amino

acids

Polypeptide

Synthesis

of protein

1

2

3

Slide56

DNADNA is a double helix of anti-parallel strands held together by H-bonds between base pairs

Each strand is a polymer of nucleotides

A nucleotide consists of a sugar, a phosphate, and a Nitrogenous base

The sugar and phosphate make up the backbone of each DNA strand

The N-base sticks inside the backbone and makes up the “rungs of the ladder”

Slide57

Fig. 16-7a

Hydrogen bond

3



end

5



end

3.4 nm

0.34 nm

3



end

5



end

(b) Partial chemical structure

(a) Key features of DNA structure

1 nm

Slide58

Fig. 5-27

5



end

Nucleoside

Nitrogenous

base

Phosphate

group

Sugar

(pentose)

(b) Nucleotide

(a) Polynucleotide, or nucleic acid

3



end

3



C

3



C

5



C

5



C

Nitrogenous bases

Pyrimidines

Cytosine (C)

Thymine (T, in DNA)

Uracil (U, in RNA)

Purines

Adenine (A)

Guanine (G)

Sugars

Deoxyribose (in DNA)

Ribose (in RNA)

(c) Nucleoside components: sugars

Slide59

DNA vs RNA

DNA is double stranded, whereas RNA is single stranded

DNA uses

deoxyribose

as the central sugar, whereas RNA uses ribose

The 4 bases in DNA are A, C, G, and T

The 4 bases in RNA are A, C, G, and U

Slide60

Fig. 5-27ab

5

'

end

5

'C

3

'C

5

'C

3

'C

3

'

end

(a) Polynucleotide, or nucleic acid

(b) Nucleotide

Nucleoside

Nitrogenous

base

3

'C

5

'C

Phosphate

group

Sugar

(pentose)

Slide61

Fig. 5-27c-2

Ribose (in RNA)

Deoxyribose (in DNA)

Sugars

(c) Nucleoside components: sugars

Slide62

Fig. 5-27c-1

(c) Nucleoside components: nitrogenous bases

Purines

Guanine (G)

Adenine (A)

Cytosine (C)

Thymine (T, in DNA)

Uracil (U, in RNA)

Nitrogenous bases

Pyrimidines

Slide63

Nucleic acidsDNA and RNA serve as genetic information



they are the blueprint to make proteins

Protein function is based on structure, which is based on the sequence of amino acids

DNA serves as a blueprint for proteins through the sequence of bases that make up an individual gene

Through the genetic code, the sequence of bases gets translated into the sequence of amino acids to make up different proteins

Slide64

Fig. 17-5

Second mRNA base

First mRNA base (5 end of codon)

Third mRNA base (3 end of codon)

Slide65

ChromosomesThe human genome consists of 3

Gbp

of DNA

If unwound, this makes up 6 feet of DNA that must fit into each and every cell of the body

Therefore, DNA in a cell cannot be allowed to completely unwind

Instead, in a cell DNA is wrapped around proteins called

histones



chromosomes

A human cell has 46 chromosomes; i.e. 46 segments of DNA wrapped around proteins

These chromosomes come in homologous pairs – one from mom and one from dad

Slide66

Fig. 16-21a

DNA double helix (2 nm in diameter)

Nucleosome

(10 nm in diameter)

Histones

Histone tail

H1

DNA, the double helix

Histones

Nucleosomes, or “beads on a string” (10-nm fiber)

Slide67

Fig. 16-21b

30-nm fiber

Chromatid

(700 nm)

Loops

Scaffold

300-nm fiber

Replicated chromosome (1,400 nm)

30-nm fiber

Looped domains (300-nm fiber)

Metaphase chromosome

Slide68

Figure 26-1

Sex Determination Is Directed By Our Genome

Humans have 23 pairs of chromosomes

22 pairs of

autosomes

X and Y = 1 pair of sex chromosomes

Slide69

Prokaryotes vs Eukaryotes

No nucleus

vs

True nucleus

Many similarities

Common biological macromolecules

Common genetic code

Common metabolic pathways

Common physical/cell structure

Many differences

Size

Cellular complexity

Metabolic diversity

Slide70

Prokaryotes

Lack nucleus

Lack various internal structures bound with

phospholipid

membranes

Are small (~1.0 µ

m

in diameter)

Have a simple structure

Include bacteria and

archaea

© 2012 Pearson Education Inc.

Prokaryotic and Eukaryotic Cells: An Overview

Slide71

Figure 3.2 Typical prokaryotic cell

Ribosome

Cytoplasm

Nucleoid

Glycocalyx

Cell wall

Cytoplasmic membrane

Inclusions

Flagellum

Slide72

Eukaryotes

Have nucleus

Have internal membrane-bound organelles

Are larger (10–100 µm in diameter)

Have more complex structure

Include algae, protozoa, fungi, animals, and plants

© 2012 Pearson Education Inc.

Prokaryotic and Eukaryotic Cells: An Overview

Slide73

Figure 3.3 Typical eukaryotic cell

Nucleolus

Cilium

Ribosomes

Nuclear envelope

Nuclear pore

Lysosome

Mitochondrion

Centriole

Secretory vesicle

Golgi body

Transport vesicles

Rough endoplasmic

reticulum

Smooth endoplasmic

reticulum

Cytoplasmic

membrane

Cytoskeleton

Slide74

CellsA cell is the functional unit of biology

All living things are made up of cells

A cell must contain the information and ability necessary to maintain itself and reproduce itself

Therefore, all cells must contain 4 basic components

Chromosomes: genetic information for the cell

Cell/plasma membrane: semi-permeable boundary

Ribosomes

: protein factory of the cell

Cytosol

/cytoplasm: the internal liquid portion of the cell

Slide75

Eukaryotic cellsHuman cells are eukaryotic

Eukaryotes are defined by having a nucleus (and other internal membrane-bound organelles)

These organelles allow for compartmentalization of individual functions for the cell

Slide76

NucleusThe defining feature of a eukaryotic cell

It is a double-

membraned

organelle with the primary role of storing and protecting DNA

In order to fit inside the nucleus (or cell in general), the DNA gets wrapped around proteins



chromosome

Within the nucleus is the nucleolus, the site of ribosome production

To move RNA and

ribosomes

out of the nucleus, it must contain nuclear pores, through which movement is regulated

Slide77

Fig. 6-10

Nucleolus

Nucleus

Rough ER

Nuclear lamina (TEM)

Close-up of nuclear envelope

1 µm

1 µm

0.25 µm

Ribosome

Pore complex

Nuclear pore

Outer membrane

Inner membrane

Nuclear envelope:

Chromatin

Surface of

nuclear envelope

Pore complexes (TEM)

Slide78

RibosomesRibosomes

are “protein factories”

They translate RNA into proteins in the cell cytoplasm

Ribosomes

are found in two locations, free-floating in

th

cytoplasm or bound to the rough ER

Free-floating

ribosomes

tend to make proteins that will function within the cytoplasm or nucleus

Bound

ribosomes

tend to make proteins that will function within an organelle or will be secreted out of the cell

Slide79

Fig. 6-11

Cytosol

Endoplasmic reticulum (ER)

Free ribosomes

Bound ribosomes

Large subunit

Small subunit

Diagram of a ribosome

TEM showing ER and ribosomes

0.5 µm

Slide80

Endoplasmic reticulum (ER)Organelle contiguous with the outer nuclear membrane, whose job is typically production

Two types: rough and smooth

Rough ER: looks “rough” because of the presence of

ribosomes

on the surface; makes proteins

Smooth ER: typically involved in lipid synthesis and sugar storage/modification

Slide81

Fig. 6-12

Smooth ER

Rough ER

Nuclear envelope

Transitional ER

Rough ER

Smooth ER

Transport vesicle

Ribosomes

Cisternae

ER lumen

200 nm

Slide82

Golgi apparatus (body)The storage and transport center of the cell (FedEx)

Products from the ER get delivered to the Golgi, which packages them, modifies them as needed, and directs them to the correct location within or out of the cell

Also, products brought into the cell often get directed to the Golgi for proper sorting

Consists of stacked membrane sacks

Products get delivered by small transport vesicles

Slide83

Fig. 6-13

cis

face

(“receiving” side of Golgi apparatus)

Cisternae

trans

face

(“shipping” side of Golgi apparatus)

TEM of Golgi apparatus

0.1 µm

Slide84

Lysosome/Peroxisome

Two organelles involved in breakdown

As cellular portions get “old and worn-down,” or as external products are engulfed and must get broken down, they are sent to these organelles

Peroxisome

Oxidative breakdown

Uses toxic oxygen species like peroxide &

superoxides

Lysosome

(not found in plants)

Enzymatic breakdown

Uses

degradative

enzymes to digest macromolecules

Slide85

Fig. 6-14

Nucleus

1 µm

Lysosome

Digestive

enzymes

Lysosome

Plasma

membrane

Food vacuole

(a) Phagocytosis

Digestion

(b) Autophagy

Peroxisome

Vesicle

Lysosome

Mitochondrion

Peroxisome

fragment

Mitochondrion

fragment

Vesicle containing

two damaged organelles

1 µm

Digestion

Slide86

VacuolesMany cells need to store components

For storage, vesicles will congregate into one organelle called a storage vacuole

Different types of cells have individual vacuoles to store various different molecules

Plant cells often contain a large Central Vacuole, which stores primarily water and provides rigidity to the cell

Slide87

Fig. 6-15

Central vacuole

Cytosol

Central vacuole

Nucleus

Cell wall

Chloroplast

5 µm

Slide88

Fig. 6-16-3

Smooth ER

Nucleus

Rough ER

Plasma membrane

cis

Golgi

trans

Golgi

Slide89

MitochondriaPowerhouse of the cell

Site of

Cellular Respiration

, where

ATP

is made

ATP: adenosine

triphosphate

Adenine + ribose + 3 phosphates

cellular battery used to charge chemical reactions

All cellular ATP is charged in the mitochondria, then gets delivered to other parts of the cell where it is broken down into ADP

Breaking the terminal phosphate bond releases energy, which can be used to power other chemical reactions

Slide90

Fig. 6-17

Free ribosomes

in the mitochondrial matrix

Intermembrane space

Outer membrane

Inner membrane

Cristae

Matrix

0.1 µm

Slide91

Fig. 9-UN3

becomes oxidized

becomes reduced

Slide92

Fig. 8-12

P

i

ADP

+

Energy from

catabolism (exergonic,

energy-releasing

processes)

Energy for cellular

work (endergonic,

energy-consuming

processes)

ATP

+

H

2

O

Slide93

Fig. 9-6-3

Mitochondrion

Substrate-level

phosphorylation

ATP

Cytosol

Glucose

Pyruvate

Glycolysis

Electrons

carried

via NADH

Substrate-level

phosphorylation

ATP

Electrons carried

via NADH and

FADH

2

Oxidative

phosphorylation

ATP

Citric

acid

cycle

Oxidative

phosphorylation:

electron transport

and

chemiosmosis

Slide94

ChloroplastFound only in plant cells

Site of photosynthesis

Photosynthesis: Using light energy to synthesize glucose from CO

2

in the air

Slide95

Fig. 6-18

Ribosomes

Thylakoid

Stroma

Granum

Inner and outer membranes

1 µm

Slide96

CytoskeletonCells are not just free-floating bags of organelles, but instead are full of internal structure

This internal structure comes from their cytoskeleton

There are 3 main classes of

cytoskeletal

molecules

Microfilaments: smallest type, made of

actin

Intermediate filaments: diverse array of proteins

Microtubules: largest type, made of

tubulin

The cytoskeleton provides internal structure, but is also very important for movement of the cell and organelles

Slide97

Table 6-1

10 µm

10 µm

10 µm

Column of tubulin dimers

Tubulin dimer

Actin subunit





25 nm

7 nm

Keratin proteins

Fibrous subunit (keratins coiled together)

8–12 nm

Slide98

Fig. 6-23

5 µm

Direction of swimming

(a) Motion of flagella

Direction of organism’s movement

Power stroke

Recovery stroke

(b) Motion of cilia

15 µm

Slide99

Cellular connections

For

multicellular

organisms, cells must be able to communicate outside individual cells to work together

Many cells are connected to each other, creating layers of tissues and organs

These cells are often connected to an extracellular matrix (ECM) or basement membrane

Many cells are interconnected through communication sites called tight/gap junctions (primarily in animals) or

desmosomes

(primarily in plants)

Slide100

Fig. 6-32

Tight junction

0.5 µm

1 µm

Desmosome

Gap junction

Extracellular

matrix

0.1 µm

Plasma membranes

of adjacent cells

Space

between

cells

Gap

junctions

Desmosome

Intermediate

filaments

Tight junction

Tight junctions prevent

fluid from moving

across a layer of cells