Download Chapter 7: CELL STRUCTURE Section 1 – Introduction to Cells

Chapter 7: CELL STRUCTURE
I. Section 1 – Introduction to Cells
WHY IT MATTERS – Why are we studying cells?
All living things are made of one or more cells.
A. The Discovery of Cells
1. Go back to chapter 1 or use your notes to list the 7 characteristics of life.
a. Living things are made of cells.
b. Metabolism
c. Homeostasis
d. Heredity/DNA
e. Growth & Development
f. Reproduction
g. Respond & Adapt
2. So, how do living things differ from nonliving things?
All living things posses ALL 7 characteristics of life; non-living things do NOT.
3. The invention of what instrument allowed us to see cells?
MICROSCOPE
4. In what year were cells discovered & by whom?
1665 – Robert Hooke (Englishman)
5. Why did Hooke name his discovery “cells”?
The cells in the thin slice of cork reminded him of the rooms (cells)
monks lived in at the monastery.
6. In 1675, what did Anton van Leeuwenhoek discover?
Invents the compound microscope; microscope with 2 lenses.
B. Cell Theory
1. In 1838, what did the German botanist, Matthias Schleiden, conclude?
All plants are made of cells.
2. What is a botanist? Scientist who studies plants.
3. In 1839, what did the German zoologist, Theodor Schwann, conclude?
All animals are made of cells.
4. What is a zoologist? Scientist who studies animals.
5. In 1858, what does the German physician, Rudolph Virchow, propose? First
to observe cells dividing; concludes that cells only come from other living
cells (pre-existing cells).
6. What does the Cell Theory state about cells?
a. All living things are made of one or more cells.
b. Cells are the basic units of structure & function of all living things.
c. All cells come from existing living cells.
C. Looking at Cells
1. How many cells in the human body? About 100 trillion
2. Are all cells the same? Explain. No, they have the same basic
structures/organelles, but their size & shapes may vary depending on the job
they perform.
3. Why must cells be small? They work more efficiently than large cells.
4. What substances do cells need to take into their cytoplasm?
OXYGEN, NUTRIENTS/FOOD, WATER
5. What substances do cells need to release from their cytoplasm?
CARBON DIOXIDE, WASTES, EXCESS WATER
6. What limits the size that a cell can grow to?
The cell membrane determines the size of the cell.
7. What part of the cell represents its surface area?
The surface area of the cell is its CELL MEMBRANE; ALL cells are surrounded
by a cell membrane. Cell membrane protects the cell & regulates what goes
in & out of the cell.
8. What part of the cell represents its volume?
CYTOPLASM – the liquid inside ALL cells.
9. Is it better to be a large cell or a small cell? Explain your answer.
Better to be a small cell because the small cell has more surface area (cell
membrane) to let substances in & out & less volume (cytoplasm) for the
substances to travel through.
10. Are all cells the same shape? Explain.
No, they come in a variety of shapes, depending on their job.
D. Cell Features
1. Identify & describe the 4 structural features ALL cells have in common.
a. Cell Membrane – surrounds ALL cells. Protects the cell & regulates
what enters & leaves the cell. (aka: plasma membrane)
b. Cytoplasm – the fluid within ALL cells.
c. Ribosomes – make proteins for ALL cells.
d. DNA & RNA (nucleic acid) – DNA carries hereditary traits (genes);
RNA helps in building of proteins. Both are found in ALL cells.
2. Features of Prokaryotic Cells
a. What group of organisms are prokaryotes? Bacteria – these cells do NOT
have a NUCLEUS or organelles.
b. Identify the 5 main features or parts of a prokaryotic bacterial cell. CELL
WALL, CELL MEMBRANE, CYTOPLASM, RIBOSOMES, DNA & RNA
c. How long have bacteria been on Earth?
3.5 BILLION YEARS
(NOTE: Earth is 4.5 – 4.6 billion years old)
3. Features of Eukaryotic Cells
1. Define eukaryote. ANY CELL THAT HAS A NUCLEUS & ORGANELLES.
Ex: plants, animals, protists, fungi
2. What type of cells are all multicellular organisms made of?
Eukaryotic Cells
3. Which cells, prokaryotic or eukaryotic, carry out more specialized
functions? Eukaryotic cells
4. When did eukaryotic cells first appear on Earth?
1.5 BILLION YEARS AGO
5. What 2 features make eukaryotic cells different from the prokaryotic
bacterial cells?
a. Having a nucleus
b. Having organelles
6. What are organelles? Means “tiny organs”. Organelles are tiny
structures found inside the cytoplasm of all eukaryotic cells. Ex:
nucleus, chloroplasts, mitochondria, vacuoles
II. Section 2 – Inside the Eukaryotic Cell
WHY IT MATTERS – How will knowing how your cells work help you?
Helps us to better understand how our bodies work.
A. The Framework of the Cell – The Cytoskeleton
1. What is the cytoskeleton & what does it do for cells?
Cyto = cell The cytoskeleton is the framework of all cells; supports the cell &
gives it shape. Made of PROTEIN and found in all eukaryotic cells.
2. What structures in your body are similar to the cytoskeleton of the cell? Your
bones/skeleton
3. Identify the 3 types of cytoskeleton fibers & tell what each one does.
a. Microtubules – largest parts of the cytoskeleton; made of TUBULIN protein
b. Intermediate fibers – medium-sized fibers in the cytoskeleton.
c. Microfilaments – smallest parts of the cytoskeleton; made of ACTIN protein
(this protein is also found in our muscle cells & helps them contract & relax)
B. Directing Cellular Activity
1. Which group of organic molecules is responsible for almost all cellular activity?
Proteins
2. What molecule has the instructions for making proteins?
DNA
3. Why is the DNA of eukaryotic cells located in the nucleus?
a. Keeps the DNA separated from the rest of the activities going on in the cell.
b. It’s protected inside the nucleus from being damaged or destroyed.
4. Nucleus – control center/brain of the cell; directs all cell activities.
 Identify the parts of the nucleus.
a. Nuclear envelope/membrane – surrounds the nucleus; has pore that allows
certain substances to enter & leave the nucleus.
b. Nuclear pores – small openings in the nuclear membrane; allow substances
to pass in & out of the nucleus.
c. Nucleolus – area of the nucleus where ribosomes are made; every cell has
at least one nucleolus.
d. Nucleoplasm – liquid inside the nucleus.
e. Chromosomes/Chromatin – carries hereditary information/genes in the
form of DNA.
5. Ribosomes – protein factories
a. What are ribosomes made of? RNA & protein
b. Where are ribosomes located in the cell? Floating in the cytoplasm/cytosol
& attached to the endoplasmic reticulum (ER)
c. Which ribosomes make proteins that will stay in the cell?
The ribosomes floating in the cytoplasm (free ribosomes).
d. Which ribosomes make proteins that will leave the cell?
The ribosomes attached to the endoplasmic reticulum (bound ribosomes).
C. Protein Processing
1. Endoplasmic Reticulum (ER) – the highway of the cell
a. What does the ER do for the cell? Allows proteins to be transported
throughout the cell & to the Golgi bodies/Golgi apparatus.
b. How does the rough ER differ from the smooth ER?
Rough ER has ribosomes attached to its outer surface; smooth ER does not.
c. Function of the rough ER? To produce proteins that will eventually be
exported from the cell.
EX: estrogen & testosterone are made in the ovaries & testes; must leave
those cells & go to other cells in the body to give you your secondary sex
characteristics.
d. Function of the smooth ER? To produce lipids/fats & other proteins that
remain in the cell.
2. What is a vesicle? A small structure in the cell that contains materials; produced
by the ER & Golgi.
3. Golgi Apparatus – the UPS of the cell; packaging & shipping organelles
a. What is the Golgi apparatus made of? Stack of flattened, fluid filled
membranes; looks like a stack of pancakes.
b. What does the Golgi apparatus do for the cell?
Packages & ships proteins & other materials.
D. Storage & Maintenance: Lysosomes (maintenance) & Vacuoles (storage)
1. Describe the role of vesicles in the cell.
Stores materials. Ex: lysosomes & vacuoles
2. Lysosomes – describe their 2 main functions
Contain digestive enzymes
a. Digest old, worn out organelles. They surround the worn out organelle take
it in & break it down.
b. In order for food in a food vacuole to be digested the food vacuole must
fuse/join with a lysosome. The digestive enzymes in the lysosome will
combine with the food in the food vacuole & digest the food.
3. Central Vacuole – main vacuole
a. What cells have a large central vacuole?
plant cells
b. What is the function of the central vacuole?
Stores water which helps maintain the shape of the
plant cell & can be used for photosynthesis.
4. Contractile Vacuoles – what do they do for cells?
Pumps excess water out of the cell; usually found in Protist cells like Amoeba &
Paramecium
5. Food Vacuoles - what do they do for cells?
Contains food that the cell needs to digest; must combine with a lysosome so the
enzymes can digest the food.
6. Waste Vacuoles – what’s their function? To remove wastes from the cell. What
were they before they became waste vacuoles? Food vacuoles.
E. Energy Production – chloroplasts & mitochondria produce food/energy for cells.
a. Chloroplasts – go through the process of photosynthesis
 What types of cells contain chloroplasts?
Eukaryotic plant cells & some Protists like Euglena.
 Function – to produce glucose/food for the cell by the process of
photosynthesis. Contains the green pigment chlorophyll.

Structure – Made up of 3 membranes (outer & inner membranes & the
thylakoid membrane). Also contains liquid called stroma, ribosomes, &
DNA; chloroplasts can reproduce by binary fission.
b. Mitochondria – go through the process of cellular respiration
 What types of cells contain mitochondrion?
ALL eukaryotic cells (protists, animal, plant & fungi)
 Function – Produces energy/ATP for the cell by breaking down glucose.
 Structure – Surrounded by 2 membranes. Contains liquid called matrix,
ribosomes, & mitochondrial DNA; mitochondria can reproduce by binary
fission.
 What cells in your body contain many mitochondria? Heart & all
muscles.
 NOTE: Chloroplasts & mitochondria are similar in structure to bacteria;
chloroplasts & mitochondria are related to bacteria.
F. Cell Wall
1. What cells have cell walls?
Prokaryotic bacteria, eukaryotic fungi & plant cells.
2. Function – Gives the cells support/shape, structure, & protection.
3. Structure – Made of cellulose & lignin.
G. Go back through the study guide & list at least 3 ways plant cells differ from animal
cells.
PLANT CELLS
ANIMAL CELLS
Cell Wall
NO Cell Wall
Chloroplasts
NO Chloroplasts
Central Vacuole
Several small vacuoles
NO Centrioles
Centrioles (involved in cell division)
No flagellum or cilia
Some cells have flagellum (sperm) & cilia
(trachea cells & oviducts/fallopian tubes)
III. Section 3 – From Cell To Organism
A. Comparison of Prokaryotic & Eukaryotic Cells – list the differences
Prokaryotic Cells
Eukaryotic Cells
(bacteria)
(plants, animals, protists, fungi)
1. NO nucleus
1. HAVE a nucleus
2. DO NOT have organelles
2. HAVE organelles
surrounded by membranes
B. Levels of Organization
1. Cells - building blocks of all living things.
2. Tissue - group of cells that have similar structures & functions. Ex: muscle tissue,
nerve tissue, connective tissue, blood
3. Organs - different organized tissues working together & having a specific
function. Ex: intestines, liver, kidneys, heart, colon/large intestine, brain, skin
4. Organ System - several organs that carry out major body functions. Ex: nervous
system, circulatory, respiratory, digestive, muscular, skeletal, excretory,
reproductive, endocrine (hormones), immune, integumentary
5. Organism – may just be made of one or more cells, or it may have cells + tissues,
or it may have cells, tissues, & organs, or it may have cells, tissues, organs, &
systems.
C. Body Types – define the following terms & give an example of an organism
representing the group.
1. Unicellular – organism made of one cell.
Ex: Bacterium, Amoeba, Paramecium, Euglena
2. Colonial – organism made of groups of cells, but each cell carries out its own
function; does not depend on the other cells in the group. Ex: Volvox
3. Multicellular – organisms made of MANY cells which are interdependent on one
another. Ex: wolf, human