Biology - Cell Structure & Function Chapter 3

Bio 0600
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Three main points of Cell Theory

1) All living things are made up of cells
2) Cell are the basic units of structure and function in living things
3) Living cells come only from other living cells
A cell's size is limited by its ______.
Surface area to volume ratio
What must a cell be large enough to do?

a) hold its organells
b) perform chemical reactions
What must a cell be small enough to do?

Have enough surface area to supply its volume with nutrients
Surface area equation
length X width X number of surfaces
Volume equation
length X width X height
Surface area to volume ratio equation

surface area
As a cell grows, what happens to its surface area to volume ratio?
It decreases

A cell cube has 3cm/side, what is its:
1) surface area
2) volume
3) Simpliest ratio

1) 54cm2
2) 27cm2
3) 2:1
When a cell grows and it's S.A. to V.R. decreases, what effects does this have of diffusion?
Diffusion decreases and becomes less efficient

When a cell divides, what happens to its surface area and volume?

They decrease causing the ratio to increase and diffusion rate to increase.
Because the volume decreases more in comparision to the surface area
Is cell division beneficial to the rate of diffusion?

How big is a prokaryote cell?

2 - 8 micrometers
Does a prokaryote cell have a nucleus?
Where is DNA located in a prokaryote cell?
In the cytoplasm
Does a prokaryote cell has a cell wall? +
Yes, non-cellulose
Are there organelles in the prokaryote cell? +
A few, but they are nonmembranous
Is there mobility in a prokaryote cell? Flagellum?
Yes, there is one or more flagellum.
What are the features of a bacillus cell?

a) rod shaped
b) areobic (needs oxygen)
c) often occurs in chain
What are the features of a cuccus cell?

a) spherical
b) occurs singular, paired or chains of clusters
What re the features of a spirrillum cell?
a) spiral shape
Gram positive's cell wall & stain

Gram negative's cell wall & stain

Peptidoglycan & lipopolysaccharide

Facilitated transport goes from _____ to _____ concentration.
Why is it a passive transfer?

High to low
Because no energy is needed, only a protein carrier
Embedded proteins in bilayer

Active transport goes from _____ to _____ concentration.
Why is ATP required?

Low to high
Because solute must travel against concentration
What are the special proteins on bilayer called?
What does APT stand for?
Adenosine Triphosphate

Does not involve/cannot enter what?
Qualitative size of molecule that cannot fit though?
What happens?

Protein channels
They fuse to outer surface of the plasma membrane, the membrane indents and he molecule is absorbed.
What is phagocytosis?
Cell eating - white blood cell engulfs and digests a pathogen
What is pinocytosis?
Ingestion of liquid
What is exocytosis?

Process by which a cell will expel a molecule it has made
Secretory vessicle containing a large molecule fusus with the interior of the plasm membrane and expels it contents from the cell.
What is the nucleus composition?

Double membrane (nuclear envelope)
Porous (nuclear pores)
Semifluid interior nucleoplasm
Unique pH
Chromatin (long strands of DNA)
What is the function of the nucleus?

DNA: contains genes (recipe) for protein synthesis
Process called transcription
Where is the nucleolus found?
Inside the nucleus
What is the composition of the nucleolus?
Dense mass of rRNA, ribosome subunit proteins

What is:

ribosomal ribonucleic acid
transfer ribonucleic acid
messenger RNA
What is a ribosome?
the protein manufacturing machinery of all living cells

In what cells is the nucleus found?
Plant and animal cells
In what cells is the Ribosome found?
Plant, animal and prokaryotes cells
What does rER stand for?
rough Endoplasmic Reticulum
Where is the ribosome located?

a) studded on the exterior surface of rER
b) cytoplasm-free ribosomes
What is the composition of the ribosome?

Two subunits:
- one smaller than the other
- each with a unique mix of proteins
What is the function of the ribosome?
Work bench for sythesis of the polypeptide chain (1*)
What is the process of the ribosome?
What is DNA's special feature and role?

SF: genetic information
R: template for mRNA synthesis during transcription
What is mRNA's special feature and role?

SF: codons
R: sequences of 3 RNA bases (codon) complementary to DNA
What tRNA's special feature and role?

SF: anticodon
R: sequence of 3 RNA bases (anticodon) complentary to mRNA codon
What is rRNA's special feature and role?

SF: ribosome
R: site of polypeptide synthesis during translation
What is amino acid's special feature and role?

SF: building block of proteins
R: transported to ribosome by tRNA during translation
What is protein's special function and role?

SF: macromolecule essential to life
R: amino acid joined in a specific and predetermined order by DNA
Where are the endoplasmic reticulum (rough and smooth) found?
In plant and animal cells
Where is the rough endoplasmic reticulum located?
Nuclear envelope
What is the compostion of the rough endoplasmic reticulum?

Interconnected tubes/sacs
outside surface studded with ribosomes
Inside fluid filled with protein enzymes
20 - 40 levels of proteins
Where is the smooth endoplasmic reticulum located?
The rough endoplasmic reticulum
How is the smooth endoplasmic reticulum composed?

Membranous interconnected tubules
No ribosomes
What are the 5 functions of the smooth endoplasmic reticulum?

1) synthesis of lipids
2) produces testosterone and estrogen
3) in liver cells produces enzymes for detox
4) in muscle stores calcium
5) synthesis transport vessels to golgi apparatus
In what cells is the golgi apparatus found?
Plant and animal cells
What is the location of the golgi apparatus?
Between the rER and sER and plasma membrane.
What is the composition of the golgi apparatus?

Series of flat sacs
Vacules "bubbling"
What is the function of the golgi apparatus?

Packaging and receiving secretion:
Receive from rER: protein and a sugar (glyoprotein)
Reveives from sER: lipid and adds a sugar (glycolipid)
Synthesis lysosomes
In what cells are the lysosomes found?
Animal cells
Where is the lysosome located?
What is the composition of the lysosome?

Membranous vacuole
Contains digective enzymes
What are the 4 functions of the lysosome?

1) digestion: enzymes digest carbs, lipids, protein and nucleic acid
2) defence: white blood cells engulf pathagens
3) cell clean up: digest old organelles
4) embryonic function: digest webbing between fingers and toes in embryo
In what cells are the vacuoles found?
In the plant and animal cells
What is the composition of the vacuoles?
Membrane bound various sizes and functions
In what cells is the peroxisomes found?
Plant and animal cells
What is the composition of the peroxisome?
Membrane vacuole containing many enzymes
In what cells are the mitochondria found?
Animal and plant cells
Where is the mitochandria located?
What does the mitochandria look like?
7 micrometers length, bean shape brown

What is the composition of the mitochondria?

Double membrane
Outer membrane: porous
Inner membrane: porous, enfolded

Cristae: individual folds
Intermembrane space: between outer and inner membrane, watery enzymes
Matrix: jelly-like fluid; contain ribosomes, oxygen, enzyme and DNA
What is the function of the mitochondria?

Site of cellular respiration: glucose to ATP
ATP synthesis
What are the unique features of mitochondria?

a) ability to reproduce/divide
b) liver cell & muscle fiber: greater than 1000 mitochondria per cell
In what cells is the cytoskeleton found?
In the plant and animal cells
What does the cytoskeleton of a cell consist of?
Protein fibers forming a thick network with the cytoplasm
What are the primary functions of the cytoskeleton?
Framework, support, movement of organelles and anchoring organelles are in place.
What are 3 types of proteins of fibers which make up a cytoskeleton?

1) microfilament
2) intermiate filaments
3) microtubules

- small fibersof actin protein
- found in muscle tissue and account for muscle cantraction
- functions in cell division by the formation of the cleavage furrow during telophrase
Intermediate filaments

- slightly larger diameter than microfilaments
- consists of fibrous proteins

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