Hit1614-HBHD-Ch3

Copyright © 2015 Wolters Kluwer Health | Lippincott Williams & Wilkins
Chapter 3
Cells and Their Functions

Copyright © 2015 Wolters Kluwer • All Rights Reserved
Overview

Key Terms
active transport filtration mitosis
cancer gene mutation
carcinogen hemolysis nucleus
chromosome hypertonic organelle
cytology hypotonic osmosis
cytoplasm interphase phagocytosis
diffusion isotonic plasma membrane
DNA micrometer ribosome
endocytosis microscope RNA
exocytosis mitochondria

The Cell

Microscopes
Learning Objective
1.List three types of microscopes
used to study cells.

Cell Structure
Learning Objectives
2.Describe the composition and
functions of the plasma membrane.
3.Describe the cytoplasm of the cell,
and cite the names and functions of
the main organelles.

Movement of Substances across the
Plasma Membrane
Learning Objectives
4.Describe methods by which
substances enter and leave cells that
do not require cellular energy.
5.Explain what will happen if cells are
placed in solutions with
concentrations the same as or
different from those of the cytoplasm.
6.Describe methods by which
substances enter and leave cells that
require cellular energy.

Protein Synthesis
Learning Objectives
7.Describe the composition, location,
and function of the DNA in a cell.
8.Compare the functions of three
types of RNA in cells.
9.Explain briefly how cells make
proteins.

Cell Division
Learning Objective
10.Name and briefly describe the
stages in mitosis.

Cells and Cancer
Learning Objective
11. Discuss the cellular changes that
may lead to cancer, and list several
cancer risk factors.

Case Study
Learning Objective
12. Use the case study to discuss the
importance of the plasma
membrane to the functioning of
the body as a whole.

Word Anatomy
Learning Objective
13. Show how word parts are used to build words
related to cells and their functions.

Microscopes
Cytology
• The study of cells
Microscope
• An instrument that magnifies structures not visible to
the naked eye
• Types of microscopes:
– Compound light microscope
– Transmission electron microscope
– Scanning electron microscope

Figure 3-1 Cilia photographed under three different
microscopes.
Which microscope shows the most internal structure of the
cilia? Which shows the cilia in three dimensions?
Microscopes (cont.)

Microscopes (cont.)
✓
Checkpoints
3-1 List six characteristics of life shown by cells.
3-2 Name three types of microscopes.

Microscopes (cont.)
?
Pop Quiz
3.1 Which microscope is most commonly used in
laboratories?
A)Scanning electron microscope
B)Transmission electron microscope
C)Compound light microscope
D)Simple light microscope

Microscopes (cont.)
?
Pop Quiz Answer
3.1 Which microscope is most commonly used in
laboratories?
A)Scanning electron microscope
B)Transmission electron microscope
C)Compound light microscope
D)Simple light microscope

Cell Structure (cont.)
General Cell Organization
• Plasma membrane
• Nucleus
• Cytoplasm
– Cytosol
– Organelles

Figure 3-2 A generalized animal cell, sectional view.
What is attached to the ER to make it look rough? What is
the liquid part of the cytoplasm called?

Plasma Membrane
• Encloses cell contents
• Regulates what enters and leaves cell
• Participates in many cell activities (e.g., growth,
reproduction, cell-to-cell interactions)
• Plasma membrane components
– Phospholipid bilayer
– Cholesterol
– Proteins

Table 3-1 Proteins in the Plasma Membrane and Their
Functions

Figure 3-3 The plasma membrane.
Why is the plasma membrane described as a bilayer?

Plasma Membrane (cont.)
• Membrane potential
– The difference in electric charge on either side of the
plasma membrane
– Caused by separation of positive and negative ions
and proteins on either side of the membrane
– Ion concentrations are determined by
• Channels
• Pumps
• Membrane potential allows the plasma membrane to act
as a battery. It uses electrical energy to power
membrane functions.

Nucleus
• Largest organelle of cell
• Surrounded by a nuclear membrane
• Contains
– Chromosomes
• Units of heredity; govern all cellular activity
– Nucleolus
• Assembles ribosomes

Cytoplasm
• Material between the nuclear membrane and plasma
membrane
– Cytosol
• Fluid portion of cytoplasm
– Organelles
• Specialized cell structures that perform different
cell functions

Table 3-2 Cell Parts
Name Description Function
PLASMA MEMBRANE Outer layer of the cell; composed mainly of lipids and
proteins
Encloses the cell contents; regulates what
enters and leaves the cell; participates in
many activities, such as growth,
reproduction, and interactions between cells
Microvilli Short extensions of the plasma membrane Absorb materials into the cell
NUCLEUS Large, membrane-bound, dark-staining organelle near
the center of the cell
Contains the chromosomes, the hereditary
structures that direct all cellular activities
Nucleolus Small body in the nucleus Makes ribosomes
CYTOPLASM Colloid that fills the cell from the nuclear membrane to
the plasma membrane
Site of many cellular activities; consists of
cytosol and organelles
Cytosol The fluid portion of the cytoplasm; contains water,
enzymes, nutrients, and other substances
Surrounds the organelles; site of many
chemical reactions and nutrient storage
Endoplasmic reticulum
(ER)
Network of membranes within the cytoplasm. Rough
ER has ribosomes attached to it; smooth ER does not
Rough ER modifies, folds, and sorts proteins;
smooth ER participates in lipid synthesis
Ribosomes Small bodies free in the cytoplasm or attached to the
ER; composed of RNA and protein
Manufacture proteins
Golgi apparatus Layers of membranes Further modifies proteins; sorts and prepares
proteins for transport to other parts of the
cell or out of the cell
Mitochondria Large organelles with internal folded membranes Convert energy from nutrients into ATP
Lysosomes Small sacs of digestive enzymes Digest substances within the cell
Peroxisomes Membrane-enclosed organelles containing enzymes Break down harmful substances
Proteasomes Barrel-shaped organelles Destroy improperly synthesized proteins
Vesicles Small membrane-bound sacs in the cytoplasm Store materials and move materials into or
out of the cell in bulk
Centrioles Rod-shaped bodies (usually two) near the nucleus Help separate the chromosomes during cell
division
SURFACE PROJECTIONS Structures that extend from the cell Move the cell or the fluids around the cell
Cilia Short, hairlike projections from the cell Move the fluids around the cell
Flagellum Long, whiplike extension from the cell Moves the cell

Surface Projections
• Structures that extend from the cell
– Cilia
• Short, hairlike projections
• Move fluids around cells
– Flagellum
• Long, whiplike extension from the cell
• Moves cell

Cellular Diversity
•Cell shape is related to cell function.
– A neuron’s long fibers transmit electric energy from
place to place in the nervous system.
– Small round red blood cells slide through tiny blood
vessels.
•Cell organelle number is related to cell function.
– Lipid-producing cells have lots of smooth ER.
– Metabolically active cells have lots of mitochondria to
manufacture ATP.

Figure 3-4 Cellular diversity.
Which of the cells shown would best cover a large surface
area?

✓
Checkpoints
3-3 List four substances found within the plasma
membrane.
3-4 What are cell organelles?
3-5 Why is the nucleus called the cell’s control center?
3-6 What are the two types of organelles used for
movement, and what do they look like?

?
Pop Quiz
3.2 What is the main substance of the plasma
membrane?
A)Cholesterol
B)Phospholipid
C)Protein
D)Steroid

?
Pop Quiz Answer
3.2 What is the main substance of the plasma
membrane?
A)Cholesterol
B)Phospholipid
C)Protein
D)Steroid

?
Pop Quiz
3.3 Which organelle generates ATP?
A)Centriole
B)Golgi apparatus
C)Mitochondrion
D)Ribosome

?
Pop Quiz Answer
3.3 Which organelle generates ATP?
A)Centriole
B)Golgi apparatus
C)Mitochondrion
D)Ribosome

Selective Permeability
• Plasma membrane regulates what enters and leaves.
• Travel across membrane is based on several factors.
– Molecular size
– Solubility
– Electrical charge
• Types of travel:
– Movement that does not require cellular energy
– Movement that requires cellular energy

Figure 3-5 Diffusion of a solid in a liquid.

Figure 3-6 Diffusion using transporters.
How would a change in the number of transporters affect a
solute’s movement by facilitated diffusion?

Figure 3-7 A simple demonstration of osmosis.
What would happen in this system if the solute could pass
through the membrane?

Figure 3-8 Osmotic pressure.
What would happen to osmotic pressure if the
concentration of solute were increased on side B of this
system?

How Osmosis Affects Cells
•Another way to think about osmosis is in terms of solute
concentration.
Water Follows the Salt
Low solute
High water
High solute
Low water
Osmosis

Table 3-3 Solutions and Their Effects on Cells

Figure 3-9 The effect of osmosis on cells.
What would happen to red blood cells in the body if blood
lost through injury were replaced with pure water?

Table 3-4 Membrane Transport
Process Definition Example
Do not require cellular energy (passive)
Diffusion Random movement of particles down the
concentration gradient (from higher concentration to
lower concentration)
Movement of gases through the membrane,
ions through an ion channel, or nutrients
via transporters
Osmosis Diffusion of water through a semipermeable
membrane
Movement of water across the plasma
membrane through aquaporins
Filtration Movement of materials through a membrane down a
pressure gradient
Movement of materials out of the blood
under the force of blood pressure
Require cellular energy
Active transport (pumps) Movement of materials through the plasma membrane
against the concentration gradient using transporters
Transport of ions (e.g., Na+
, K+
, and Ca2+
) in
neurons
Bulk transport Movement of large amounts of material through the
plasma membrane using vesicles; also called
vesicular transport
Endocytosis Transport of bulk amounts of materials into the cell
using vesicles
Phagocytosis—intake of large particles, as
when white blood cells take in waste
materials; also pinocytosis (intake of
fluid), and receptor-mediated endocytosis,
requiring binding sites in the plasma
membrane
Exocytosis Transport of bulk materials out of the cell using
vesicles
Release of neurotransmitters from neurons

Figure 3-10 Phagocytosis.
What organelle would likely help to destroy a particle taken
in by phagocytosis?

Figure 3-11 Exocytosis.

✓
Checkpoints
3-7 What types of movement through the plasma
membrane do not directly require cellular energy, and
what types of movement do require cellular energy?
3-8 What term describes a fluid that is the same
concentration as the cytoplasm? What type of fluid is
less concentrated? More concentrated?

?
Pop Quiz
3.4 Which process uses transporters but not ATP?
A)Active transport
B)Endocytosis
C)Facilitated diffusion
D)Simple diffusion

?
Pop Quiz Answer
3.4 Which process uses transporters but not ATP?
A)Active transport
B)Endocytosis
C)Facilitated diffusion
D)Simple diffusion

?
Pop Quiz
3.5 Which method transports bulk amounts of
material into the cell using vesicles?
A)Active transport
B)Endocytosis
C)Exocytosis
D)Osmosis

?
Pop Quiz Answer
3.5 Which method transports bulk amounts of
material into the cell using vesicles?
A)Active transport
B)Endocytosis
C)Exocytosis
D)Osmosis

?
Pop Quiz
3.6 Cells crenate when they are placed in
solutions that are
A)Catatonic
B)Hypertonic
C)Hypotonic
D)Isotonic

?
Pop Quiz Answer
3.6 Cells crenate when they are placed in
solutions that are
A)Catatonic
B)Hypertonic
C)Hypotonic
D)Isotonic

Protein Synthesis (cont.)
Overview
•Proteins give a cell its structure and function.
•DNA directs protein synthesis.
– Nucleotides make up DNA
– DNA organized into genes
– Genes organized into chromosomes
•RNA participates in protein synthesis but is not part of
chromosomes.

Figure 3-12 Chromosomes and DNA.

Table 3-5 Comparison of DNA and RNA
DNA RNA
Location Almost entirely in the nucleus Almost entirely in the cytoplasm
Composition Nucleotides contain adenine
(A), guanine (G), cytosine
(C), or thymine (T)
Sugar: deoxyribose
Nucleotides contain adenine (A),
guanine (G), cytosine (C), or
uracil (U)
Sugar: ribose
Structure Double-stranded helix formed
by nucleotide pairing A–T;
G–C
Single strand
Function Makes up the chromosomes,
hereditary units that control
all cellular activities; divided
into genes that carry the
nucleotide codes for the
manufacture of proteins
Manufacture proteins according
to the codes carried in the DNA;
three main types: messenger
RNA (mRNA), ribosomal RNA
(rRNA), and transfer RNA
(tRNA)

Table 3-6 The Genetic Code
Amino Acid Transcribed DNA
Triplet
mRNA tRNA
Glycine CCC GGG CCC
Proline GGG CCC GGG
Valine CAC GUG CAC
Phenylalanine AAA UUU AAA
The nucleotide triplet code in DNA and RNA is shown
for four amino acids.

Table 3-7 Role of RNA

Two-Step Process of Protein Synthesis
• Transcription
– First step; occurs in nucleus
– DNA code is transcribed into mRNA by nucleotide base
pairing
• Translation
– Second step; occurs in cytoplasm
– mRNA leaves nucleus and travels to ribosomes
– Ribosomes and tRNA translate mRNA into protein’s
amino acid sequence

Figure 3-13 Transcription.

Figure 3-14 Translation.

✓
Checkpoints
3-9 What are the building blocks of nucleic acids?
3-10 What category of compounds does DNA code for in
the cell?
3-11 What three types of RNA are active in protein
synthesis?

?
Pop Quiz
3.7 Which DNA nucleotide pairs with adenine?
A)Cytosine
B)Guanine
C)Thymine
D)Uracil

?
Pop Quiz Answer
3.7 Which DNA nucleotide pairs with adenine?
A)Cytosine
B)Guanine
C)Thymine
D)Uracil

?
Pop Quiz
3.8 Which RNA is transcribed from DNA?
A)Amino acid
B)Messenger RNA
C)Ribosomal RNA
D)Transfer RNA

?
Pop Quiz Answer
3.8 Which RNA is transcribed from DNA?
A)Amino acid
B)Messenger RNA
C)Ribosomal RNA
D)Transfer RNA

?
Pop Quiz
3.9 What is synthesized during translation?
A)Amino acid
B)Protein
C)Starch
D)Triglyceride

?
Pop Quiz Answer
3.9 What is synthesized during translation?
A)Amino acid
B)Protein
C)Starch
D)Triglyceride

?
Pop Quiz
3.10 During which phase of mitosis are
chromosomes first visible?
A)Anaphase
B)Metaphase
C)Prophase
D)Telophase

?
Pop Quiz Answer
3.10 During which phase of mitosis are
chromosomes first visible?
A)Anaphase
B)Metaphase
C)Prophase
D)Telophase

Cell Division (cont.)
Types of Cell Division
• Meiosis
– Produces gametes (n)
– Cuts chromosome number in half to prepare for union
of egg and sperm during fertilization
• Mitosis
– Produces somatic cells (2n)
– Parent stem cell gives rise to two identical daughter
cells

Preparation for Mitosis
• DNA replicates during interphase
• Identical strands held together at centromere until they
separate during mitosis
DNA replication
during interphase
Mitosis

Stages of Mitosis

Figure 3-15 The stages of mitosis.
If the original cell shown has 46 chromosomes, how many
chromosomes will each new daughter cell have?

✓
Checkpoints
3-12 What must happen to the DNA in a cell before
mitosis can occur? During what stage in the cell life
cycle does this occur?
3-13 What are the four stages of mitosis?

Cell Aging
• As cells multiply, changes occur that may lead to their
damage or death.
– Free radical injury
– Enzyme injury
– Gene mutation
– Slowing cell activity
– Apoptosis

Cells and Cancer (cont.)
Development of Cancer
• Genetic mutations may cause uncontrolled cell division.
• Cells may spread (metastasize), producing cancer.
• Cancer cells form tumors, crowding out normal cells.

Cancer Risk Factors
•Heredity
•Chemicals
•Radiation
•Diet
•Viruses

?
Pop Quiz
3.11 Which of the following is a cancer risk factor?
A)A diet rich in fruits and vegetables
B)A family history of cancer
C)Regular exercise
D)Regular use of sunscreen

?
Pop Quiz Answer
3.11 Which of the following is a cancer risk factor?
A)A diet rich in fruits and vegetables
B)A family history of cancer
C)Regular exercise
D)Regular use of sunscreen

Case Study (cont.)
• Cystic fibrosis is an inherited disease
• Ben’s parents each carried a defective gene in their DNA
and both had by chance passed copies of the gene onto
Ben
• As a result, Ben was unable to synthesize a channel
protein causing a defect in the movement of chloride
into the cell
• Abnormal chloride channel function causes many organs
to produce thick, sticky mucus resulting in effects on the
entire body), for example, the lung (difficulty breathing),
intestines (inadequate absorption of nutrients), pancreas
(inability to produce digestive enzymes)

Word Anatomy
Learning Objective
13. Show how word parts are used to build words related
to cells and their functions.

Word Anatomy (cont.)

Hit1614-HBHD-Ch3

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