BIO 143 Lecture Notes - Lecture 4: Cell Membrane, Smallest Organisms, Cell Theory

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16 Jun 2018

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Chapter 4

Cell Structure and Function

The Cell Theory

Three principles comprise the cell theory

-Every living organism is made of one or more cells

-The smallest organisms are single cells, and cells are the functional units of multicellular

organisms

-All cells arise from pre existing cells

Characteristics of Cells

All cells share common features: plasma membrane

-The plasma membrane encloses the cell and allows interactions between the cell and its

environment

-This structure is composed of lipid, protein, and carbohydrate molecules, and regulates the

passage of ions and molecules in and out of cells

-The plasma membrane and other membranes within the cell consist of a double layer of

phospholipids and cholesterol molecules in which many different proteins are embedded

-Important functions of the plasma membrane included:

1. Isolatig the ell’s otets fro the eteral eviroet

2. Regulating the flow of materials into and out of the cell

3. Allowing interaction with other cells and with the extracellular environment

-The cytoplasm consists of all the fluid and structures that lie inside the plasma membrane

but outside of the nucleus

:The fluid portion of the cytoplasm contains water, salts, and organic molecules

:Most of the ell’s etaoli ativities occur in the cell cytoplasm

-All cells use RNA as a hereditary blueprint

:Contains genes consisting of precise sequences of nucleotides

:During cell division, the original or parent calls pass exact copies of their DNA to the

daughter cells

-All cells use RNA to copy the blueprint and to guide construction of proteins

Energy

-All cells obtain raw materials and energy from their environment

-The building blocks of biological molecules such as carbon, hydrogen, oxygen, nitrogen, and

phosphorus, as well as a variety of minerals that come from the environment

-All the energy powering life on Earth originates from the sun; photosynthetic organisms

store this energy and animals obtain the energy when consumed

Major Functions of Eukaryotic Cells

Eukaryotic cells are usually larger than prokaryotic cells

-The cytoplasm of eukaryotic cells includes a variety of organelles, such a the nucleus and

mitochondria

-The cytoskeleton gives shape and organization tot eh cytoplasm of eukaryotic cells

-Organelles are attached to a network of protein fibers that make up the cytoskeleton

-The cytoskeleton is composed of three types of protein fibers

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Document Summary

Every living organism is made of one or more cells. The smallest organisms are single cells, and cells are the functional units of multicellular organisms. The plasma membrane encloses the cell and allows interactions between the cell and its environment. This structure is composed of lipid, protein, and carbohydrate molecules, and regulates the passage of ions and molecules in and out of cells. The plasma membrane and other membranes within the cell consist of a double layer of phospholipids and cholesterol molecules in which many different proteins are embedded. Important functions of the plasma membrane included: isolati(cid:374)g the (cid:272)ell"s (cid:272)o(cid:374)te(cid:374)ts fro(cid:373) the e(cid:454)ter(cid:374)al e(cid:374)viro(cid:374)(cid:373)e(cid:374)t, regulating the flow of materials into and out of the cell, allowing interaction with other cells and with the extracellular environment. The cytoplasm consists of all the fluid and structures that lie inside the plasma membrane but outside of the nucleus. :the fluid portion of the cytoplasm contains water, salts, and organic molecules.

Related Questions

LAB MODULE: BASIC MICROSCOPY â STUDY HELP

The information in this document is helpful in preparing for the Basic Microscopy Pre-Lab Quiz on Canvas and the Basic Microscopy quiz on Late Nite Labs.

Instructions:

â¢ Go to your Late Nite Labs course site and click on the Basic Microscopy link. The lab manual content will appear on the right side of the screen.

â¢ PRINT and READ all of the information found in the Basic Microscopy lab manual.

â¢ Use the information to answer the following questions.

Questions

â¢ Fill in the remainder of the chart.

Objective Lens	Objective Magnification	Ocular Magnification	Total Magnification
Scanning	4X	10X	40X
Low Power	10X	10X
High Power	40X	10X
Oil Immersion	100X	10X

â¢ Do all organisms consist of more than one cell?

â¢ What is the structural and functional unit of living things? In other words, what is considered the basic building block of LIFE?

â¢ What three structures are found in the cells of ALL organisms, both prokaryotic and eukaryotic? You may have to look at the pictures of the cells in the Basic Microscopy lab manual content to find all three structures. Note: plasma membrane = cell membrane

â¢ List the major differences in prokaryotic cells and eukaryotic cells? Include the location of genetic material in a eukaryotic versus prokaryotic cell.

â¢ List the organelles found in a eukaryotic cell that are not found in a prokaryotic cell. You may have to look at the pictures of the cells in the Basic Microscopy lab manual content to find all of these.

â¢ In eukaryotic cells, genetic information is found in the form of DNA. Is this true for prokaryotic cells?

â¢ Are flagella and cell walls unique to eukaryotes? Why or why not?

â¢ The __________is the part of a cell that allows the movement of substances into and out of the cell and protects the cell from its environment.

â¢ The__________is a substance that contains all of the dissolved and suspended ions and other molecules needed to keep the cell alive.

â¢ A__________is an organelle that serves as the site of photosynthesis in a eukaryotic cell.

â¢ Some organisms have cells that contain a__________that gives the cell a more structured shape and strengthens the cell by osmotic pressure.

â¢ Describe dark field microscopy.

â¢ Describe phase contrast microscopy.

â¢ Why do scientists use dark field microscopy and phase contrast microscopy when studying prokaryotic cells?

â¢ How does phase contrast microscopy help scientists visualize difficult specimens?

â¢ Fill in the remainder of the chart. The organisms studied during this lab are: Amoeba, Spirogyra, cardiac muscle, and bacteria.

Structure	Function	Organisms Studied
Plasma Membrane		Amoeba, Spirogyra, cardiac muscle, and bacteria
Cytoplasm
Nucleus	Contains the genetic material of a eukaryotic cell
Chloroplast		Spirogyra
Cell wall

Cholesterol is transported in the bloodstream in lipoproteinparticles. There are several classes of lipoprotein particles, butone of the most important classes is called Low-densitylipoproteins (LDL). LDL particles are composed of a single moleculeof a large protein called apolipoprotein, as well as thousands ofcholesterols molecules and phospholipids. Part of theapolipoprotein forms the surface of the particles and faces theaqueous phase, while other parts face the hydrophobic interior ofthe particle where they interact with cholesterol and thehydrophobic tails of the phospholipids. When cells need additionalcholesterol, they produce a receptor protein on the surface oftheir plasma membrane that binds to the apolipoprotein andinitiates the uptake of LDL particles into the cell via a processcalled endocytosis.

1. What is the likely reason that LDL particles are used totransport cholesterol in the blood stream?

a. Cholesterol in LDL particles easily inserts into lipidbilayers

b. Cholesterol id largely insoluble in aqueous solutions

c. Cholesterol is synthesized within LDL particles

d. LDL particles can form lipid rafts in the lipid bilayer

2. What is the most likely location of phospholipids in LDLparticles?

a. Bound to the hydrophilic domain of apolipoprotein

b. In the lipid bilayer that surrounds LDL particles

c. On the surface interacting with the aqueous environment aswell as interacting with the hydrophobic core of the particle

d. Within the hydrophobic core of the particle

3. What best describes the class of protein that apolipoproteinbelongs to?

a. Amphipathic proteins

b. Cell surface proteins

c. Membrane associated protein

d. Multipass membrane proteins

4. What kind of molecule on the surface of the cell would bemost likely to serve as a receptor for LDL particles?

a. a cholesterol binding protein

b. a glycolipid

c. a phospholipid

d. trans membrane protein

5. What conditions would be most likely to trigger increaseduptake of LDL particles by cells?

a. increased glycolipid synthesis

b. increased plasma membrane growth

c. increased protein secretion

d. increase protein synthesis

________30. If you are investigating the inner structure of a new cell and see that it has a significantly larger amount of RER than other cells. You would conclude the cell does a great deal of____?
A. ATP synthesis

B. protein synthesis
C. DNA synthesis
D. active transport
E. polysaccharide hydrolysis

________31. If a cell comes in contact with a toxic substance such as H2O2, it could survive as long as it has a ___ to digest it.
A. DNA
B. peroxisome

C. mitochondria
D. phospholipids
E. intermediate filaments

________32. Some cells have structures to help them withstand osmotic pressure. For example,
A. Plant cells due to their walls
B. Animal cells due to the sodium/potassium pumps

C. Bacterial cell due to their swimming

D. Viruses due to their protein coats

________33. Evolution occurs only as a cell ____.

A. They undergo mitosis
B. Change in their gene pool
C. They move from one habitat to another

D. They begin to eat different foods

________34. Ribosomes are produced in the

A. nucleoli.
B. chromatin.
C. nuclear envelopes.

D. Golgi complex. E. cisternae.

________35. Algae are often green, but there are red and brown species also. What accounts for this difference in color?
A. The chlorophyll of chloroplasts
B. The pigments in other plastids

C. The presence of a mitochondria
D. The accumulation of cellular wastes

________36. The chloroplast and other like prokaryotes have which of the following that helps with photosynthesis?
A. They live in water based environments
B. They have chloroplasts in their cytoplasm

C. Change color in the dark vs. the sun
D. They have photoreceptor proteins in their membranes or mesosomes.

________37. Located in the membrane, we see a set of proteins called receptors that only connect with or bind to specific substances. This is called __.
A. ligand specificity.
B. hormone selectivity.

C. cell tonicity.
D. water saturation. E. signal resolution.

________38. Of the following statements, we could say that ___ is false.
A. All organisms are composed of cells and cell products.
B. An organism's structure and all of its functions are due to the activities of cells.
C. The cellular organelles are the simplest structural and functional unit of life.
D. Cells come from preexisting cells.
E. Cells are made from nonliving components including the nucleus, cell membrane and cytoplasm.

________39. If it is really true that our cells are the smallest anatomical unit that meets all of the properties of life, then which of the following could imply otherwise?
A. vacuoles
B. centrioles

C. Golgi apparatus
D. mitochondria
E. endoplasmic reticulum

________40. Oxygen is an absolute need for animal and plant cells alike due to the ___.

A. RER
B. Mitochondria
C. Lysosomes

D. DNA

________41. In a plasma membrane, we expect to see the carb/protein structures to extend into the ___, but the secondary messengers to move within the __.
A. extracellular fluid; cytosol
B. cytosol; extracellular fluid

C. intracellular fluid; cytosol

D. cytosol; intracellular fluid

E. extracellular fluid; plasma

________42. Bacteria are found in all of the following habitats:

A. Caves
B. Oceans
C. Animals

D. Everywhere on Earth

________43. Two solutions are separated by a selectively permeable membrane. Solution A has a higher concentration of an impermeable solute compared to solution B. Which of the following do you expect would happen?
A. solute will move from solution A to solution B

B. solute will move from solution B to solution A

C. water will more from solution A to solution B

D. water will move from solution B to solution A E. no movement of solute or water will occur

________44. In the kidney, we notice that almost all of the cells involved in the production of urine have high concentrations of the Na+/K+ pump. Which typically works to push Na+ ___ its concentration gradient by using ___.
A. up; active transport

B. up; facilitated transport
C. up; cotransport
D. down; active transport
E. down; facilitated transport

________45. In the charts of a patient recently admitted to the hospital noted that he was taking a medication called lithium and high doses of calcium supplements. Given this, we would expect the patientâs liver to have a higher than normal amount of __ to purify out the lithium and calcium.

A. lysosomes.
B. centrosomes.
C. mitochondria.
D. peroxisomes.
E. rough endoplasmic reticulum.

________46. We have long observed that our neural cells in the brain cannot replicate or replace themselves due to the lack of ____.
A. produce ATP.
B. divide.

C. produce enzymes.
D. secrete material across their plasma membrane E. conduct electrical signals.

________47. An organismâs structure and function is ultimately due to the structure and function of itâs __.
A. Organs
B. Tissues

C. Cells

D. Nuclei

BIO 143 Lecture Notes - Lecture 4: Cell Membrane, Smallest Organisms, Cell Theory

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