Bio 002 Unit 1

Cell Theory

All living things are made up of cells
Cells are the smallest unit of life
All existing cells evolved from preexisting cells

What are the Conditions for something to be considered alive? (MR. GREy +)

M etabolism: Must have chemical reactions taking place within the cell
R espond: Must be able to respond to its environment in some way (cellular signaling)
G rowth: Must be able to grow
R eproduce: Must be able to replicate itself
E volve: Must be able to evolve throughout time (generational evolution)
- surrounded by a membrane constituting a cell
| DNA is the molecule of inheritance

Anabolic Reaction

A reaction that results in a complex molecule being created from smaller molecules

SIMPLE --\> COMPLEX

Catabolic Reaction

Reaction that breaks down a complex molecule into smaller/simpler ones

COMPLEX --\> SIMPLE

What is the general size of cells

Micrometers (um)

Do some cells die in the presence of O2?

Yes

How is DNA stored in cells?

DNA is stored as chromosomes, a complex made up of DNA strands, wrapped around histones and compressed.

About how long ago was the ancestor of all Eukaryotic organisms thought to exist?

3.5-3.8 billion years ago

What are the 2 classes of cells?

Prokaryotic Cells and Eukaryotic Cells

What is the principle factor by which cell classes are differentiated

Presence of a nucleus
Eukaryotes have a nucleus, Prokaryotes done

What is another way by which Eukaryotes are distinct from prokaryotes?

Presence of membrane bound organelles.

How many domains contain prokaryotic Cells? What are they?

2 Domains: Bacteria and Archaea

How is DNA stored in Prokaryotes

It is centrally localized in a region called the nucleoid, which is not bound by a membrane, in a CIRCULAR form

What are the characteristics of Prokaryotes?

Shape: rod-like, spiral-shaped, spherical

Single-celled organisms

Able to form multicellular complexes by joining with others to form such structures

Large in \# and reproduce very fast

Most diverse and numerous cells on Earth

Smaller in size than Eukaryotes

Lack organelles

Can be aerobic and can even have internal membranes for processes such as photosynthesis.

Able to make organic compounds from inorganic materials

How many kingdoms contain prokaryotes?

2 Kingdoms: Bacteria and Archaea

How many domains include Eukaryotes?

1 Domain: Eukarya

What are 20 organelles

* Plasma Membrane
* Cytosol
* Nucleus
* Nucleolus
* Rough ER
* Smooth ER
* Golgi Body
* Peroxisomes
* Lysosomes
* Mitochondria
* Vacuoles
* Chloroplasts
* Intermediate Filament
* Microtubules
* Actin Filament
* Centriole
* Cell Wall
* Nucleoplasm

Nucleus

Double membrane enclosed organelle that houses most of the cells genome

* Surrounded by 2 concentric membranes that make up the nuclear envelope

Nucelolus

Specific region inside the nucleus where ribosomes are made and rRNA is transcribed

Mitochondria

Double embrane enclosed organelle with inner cristae, and functions to convert glucose into chemical energy in the form of ATP, through cellular respiration.

* Contains its down DNA and replicates at a different time frame than the rest of the cell


* Exists as an endosymbiont

Chloroplast

Couble membrane enclosed organelle found in plant cells that functions to convert light into food in the form of glucose in a process called photosynthesis.

* Contains its down DNA and replicates at a different time frame than the rest of the cell
* Exists as an endosymbiont

Plasma Membrane

A selectively-permeable phospholipid bilayer made up of different types of lipids and proteins.

Cytoplasm

Everything between the nuclear envelope and the plasma membrane

Cytosol

Everything between the nuclear envelope and the plasma membrane EXCEPT the organelles.

* Functions as the site of many chemical reactions in the cell
* Acts as a buffer containing weak acids and bases that release and take out protons as needed to keep the pH of the cell relatively stable

Protoplasm

Everything within the cell membrane

Nucleoplasm

Area enclosed by the nuclear membrane

What is the main function of carbohydrates?

short term energy

Which of the following small molecules would be used to construct proteins?

Amino acids

Where are proteins that are shipped OUT of the cell made?

Ribosomes attached to the Rough Endoplasmic Reticulum

Where are proteins that are shipped to locations INSIDE the cell made?

Free ribosomes floating in the cytosol

Rough Endoplasmic Reticulum

Site of protein synthesis by attached ribosomes

* Pinches off a portion of membrane to form vesicle that contains the protein.

Smooth Endoplasmic Reticulum

Site of lipid synthesis, hormone synthesis, steroid synthesis, detoxifies certain toxins, acts as a Ca2+ storage

Golgi Body

A collection of cisternae (flattened stacks of membrane that functuions to process proteins after they have been made. This can include adding tags to them, modifying their structure, and tagging them for their destination whether in or out of the cell.

Pinches off a portion of membrane to form vesicle that contains the processed protein.

Lysosomes

Membrane enclosed sacs that contain hydrolytic enzymes in an aqueous solution of pH 5.

- Function to digest old organelles, debris, and large ingested particles, allowing for the recycling of organic matter.

- RECYCLE the cells organic matter

Vacuoles

Membrane enclosed sacs that simple hold things for the cell such as water, food, starch, etc.

* In plants, there is a central vacuole that holds all the water for the plant cell.

Centrioles

Small paired cylindrical structures that are found in the mitotic/meiotic spindles and assist during cell division.

Peroxisomes

Membrane enclosed sacs that function in detoxifying alcohols and other harmful compounds, producing and then breaking down Hydrogen Peroxide in the process.

- Also break down fatty acids

Cell Wall

A rigid layer of nonliving material that surrounds the cells of plants and some other organisms.

What separates the prokaryotic cells of Archaea and Bacteria

Bacteria have specific key components present in their cell wall that are absent in that of archaeal cells

* Archaea are most commonly found in extreme and harsh environments

What 4 kingdoms are present under the Eukarya domain

Protists
Plants
Fungi
Animals

What is primary endosymbiosis

The process in which a cell engulfs another cell with no organelles, incorporating the engulfed cell as a primary endosymbiont

What is secondary endosymbiosis

Process in which a cell engulfs another cell that already has a primary endosymbiont inside of it.

Why do cells vary so greatly in terms of appearance and function?

Cells vary so greatly on these two factors because different structures allow cells to complete their functions better. Therefore based on their function, cells conform to a certain shape.

Additionally, some cells specialize in their function.

How is the amount and spread of prokaryotes compared to that of eukaryotes

Prokaryotes are much more widespread and are present in much greater numbers in the world.

Cells of a multicellular organism can perform different functions even though they all share one \__________ by \________________

Cells of a multicellular organism can perform different functions even though they all share one GENOME by ONLY EXPRESSING CERTAIN GENES.

What is the Central Dogma of Biology?

A pattern of information transfer from DNA-\> RNA -\> Protein.
DNA can never go directly to protein.

What is a piece of evidence for all cells sharing evolutionary ancestry

Similar genes across cells of different organisms.

Ex: Eukaryotic cells share some genes with bacterial cells; Some genes of one animal or organism can be implanted into other organisms and the cells will transcribe those implanted genes as their own.

Endocytosis

The process by which a cell transports large molecules INTO the cell by pinching off a portion of the membrane to form a vesicle.

Exocytosis

The process by which a cell transports large molecules OUT OF the cell by pinching off a portion of the membrane to form a vesicle.

How does a Light Microscope work

Light is passed through a VERY THIN slice of a specimen and concentrated through magnifying lenses and projected to the eye piece allowing for viewing of the specimen at high magnification

magnification limit: 0.2 micrometers
Able to see: Some internal structures of the cell such as the nucleus, plasma membrane and the cytoplasm

What are the advantages and limitations of Light Microscopes

Advantages:
Cheap
Fast
Can view LIVING specimen


Limitations:
Can only see structures as small as 0.2 micrometers.
Limited by the low frequency of light waves.

Fluorescence Microscopy

Type of light microscope that detects fluorescent dyes which are tagged to certain components of cells such as specific proteins.

Confocal Microscopy

Light microscope that can view internal structures using a laser that can travel a specified depth.

How does an Electron Microscope work?

- uses a beam of electrons which are focused using magnets
- the electrons hit a fluorescent screen which emits visible light, producing an image

magnification limit: as small as 1 nanometer or 0.001 micrometers
Able to see: Organelles of the cell to individual molecules pres

Transmission Electron microscope

A type of electron microscope that can view the internal structures of a specimen by shooting a beam of electrons through the subject then using them to generate an image.
- Staining is possible using heavy metals that are electron dense.
Limit of resolution : 0.001 micrometer

Scanning Electron Microscope

A type of electron microscope that can view the SURFACE of any speciment at intense depth and detail by bouncing electrons off of the surface then scanning the dispersion pattern of the electrons to generate an image.

- Subject must be COATED in an electron dense metal.

- Can capture details as small as 0.003 micrometers

Limit of resolution

A measure of the ability of a microscope to distinguish adjacent objects in an image into distinct objects.

- If a microscope has a limit of resolution equal to 0.001 micrometers, it can distinguish objects as close as 0.001 micrometers apart as separate objects in the image.

What did the Light microscope contribute to the Cell Theory

Third tenant: All cells are formed by the growth and division of existing cells

What is the ancestor of eukaryotic cells most likely to be

The ancestor of Eukaryotic cells was most likely a predatory cell that engulfed other cells. This cell is most likely the cell that engulfed the bacteria that are now the mitochondria and chloroplast.

Did the ancestor of Eukaryotic cells most likely engulf mitochondria or chloroplast first? Why?

The ancestor of eukaryotic cells most likely engulfed the mitochondria first. We know this because mitochondria is present in both animal and plant cells, but the chloroplast is only present in plant cells.

Protozoan

Type of single-celled predatory eukaryote that lives by engulfing other cells.
- Not all protozoans are predatory though

Model Organisms

Organisms chosen to represent the basic characteristics of much larger branches of life.

- Studying 1 representative is much more efficient and effective than studying every single organism.

All amino acids are composed of \_______.

amino group, carboxyl group, side chain (R group)

Which of the following molecules acts as the energy store for ATP?

phosphate

* Because it takes a lot of energy to hold the 2 very negative phosphate groups together, breaking of the phosphoanhydride bond releases ALOT of energy

From Figure 2.4 in your books, what is the main reason that the Earth's crust is high in oxygen and silicon? Look at the approximate ratio of these elements!

It is the sand we find in the rocks and beaches of the planet.

Why does oxygen form bonds with its neighbors at strange angles?

Two lone pairs

Hydrogen bonds include hydrogen and what three other elements?

Oxygen, Nitrogen, Fluorine

Which of the following cannot make macromolecules?
1. Proteins
2. Carbohydrates
3. Nucleic Acids
4. Lipids
5. None of the above

Lipids

What proportion of a typical bacterial cell is water?

70%

After water and proteins, the next most common constituent of bacterial cells is?

RNA

Ribosomal subunits are held together by?

Covalent Bonds

The repeating backbone atoms of a polypeptide chain entail the following atoms...

NCCNCCNCCNCCNCCNCC

The folding of most biologically active molecules is a result of?

Non-covalent bonds

Another name for a dehydration reaction is?

Condensation Reaction

A molecule with a long string of CH and then a -COOH group at one end would be a?

Fatty Acid

Which of the following is a carbonyl group?
1. NH3
2. COOH
3. OH
4. C\=O
5. CH3

C\=O

Based on what you now know about atomic forces, why is silicon a poor second to carbon in forming large molecules?
1. There is not enough of it on Earth!
2. It has too large of an atomic radius and thus makes weaker molecules.
3. Silicon only forms three bonds with other atoms.
4. Silicon is poisonous to living things.
5. None of the above

It has too large of an atomic radius and thus makes weaker molecules

What is the purpose of a buffer?

Maintains the pH at a certain level

Which of the following has a molecular formula of 180 Daltons?
1. C6 H11 O6
2. C6 H12 O6
3. C6 H12 O4
4. C6 H12 O7
5. C7 H12 O6

C6 H12 O6

Why are electrons correctly depicted as a continuous cloud about an atomic nucleus?

There is no way of predicting exactly where an electron is at any given instant.

The central dogma refers to...

The flow of information from DNA to RNA to Protein

Which structures contain DNA in eukaryotic cells?

nucleus, mitochondrion, chloroplasts

The methyl (-CH3), hydroxyl (-OH), carboxyl (-COOH), carbonyl (-C\=O), phosphoryl (-PO3 2-), and amino (-NH2) structures are common \__________________ that are part of most \__________ molecules.

chemical groups, organic

What are the three constituents of a nucleotide?

Phosphate, Nitrogen Base, Sugar

The fundamental building block of all organic compounds in a cell is \________. This is because it can form \_______ covalent bonds, allowing for multiple complex structures.

carbon; 4

Within living most cells, there are some very common classes of organic molecules. Which of these is not one of them?

Water

Phospholipids are composed of \____.

Polar group, phosphate, glycerol, fatty acid tails

Cytoskeleton

System of protein filaments that gives the cell internal structure, strengthens the cell, allows the cell to move, provides a track for intracellular transportation, and is involved in other cellular processes

What 3 filaments make up the cytoskeleton and what are their main functions?

Actin filaments: Help the cell move and contract, and provides structure to the cell
- In plants they do not help the cell move since plant cells do not move around.

Microtubules: Function in mitosis and meiosis as part of the meiotic and mitotic spindle, pulling chromosomes apart to polar ends of the cell. ALSO act as a track for motor proteins to travel on when carrying cell components.

Intermediate Filaments: Function to strengthen the cell and holds organelles in place

Life is classified in many ways. How many classes of cells are there, based on a feature called the nucleus?

Two

Prokaryotic cells usually come in three common shaped. What are they?

spherical, rodlike, and spiral-shaped

What is Caenorhabditis elegans?

Invertebrate worm

Where would one find a nucleiod?

In prokaryotic cells

Which of these is NOT why scientists study model organisms?
1. Space constraints
2. Costs
3. Reproduction time
4. Fear of handling
5. Transparency

Fear of handling

What is Arabidopsis thaliana?

plant

What is Saccharomyces cerevisiae?

Yeast

What is Escherichia coli?

Bacteria

What is Drosophila melanogaster?

Invertebrate fruit fly

Which statement is NOT true of mitochondria?
- Mitochondria are thought to have originated from bacteria.
- Mitochondria contain their own DNA.
- Mitochondria have an inner and outer membrane.
- Mitochondria are involved in the chemical energy cycle of the cell.
- Mitochondria are not present in plant cells.

Mitochondria are not present in plant cells.

Identify the main purpose of a cell's nucleus:

* make proteins using the genetic material.
* provide energy for the cell.
* stores excess chemical reagents to aid the cytoplasmic reactions.
* allow cells to segregate their chromosomes.
* none of these answers is correct

none of the answers are correct