UNIT 1: Cell Bio; Ch. 1

What did Mattias Schleiden do?

(1838) concluded that all plant tissues are composed of cells

What did Theodor Schwann do?

(1839) he discovered that all animals are made of cells

Eukaryotes include 4 Kingdoms which are?

- Animals - Plants, including some algae. - Fungi, including mold and yeast. - Protists: Unicellular, eukaryotes that are not plants, animals, or fungi. (These include amoeba, some parasites, and some algae)

You are trying to study the size and shape of different cells and cellular compartments. which of the following would be easy to observe using a compound light microscope and simple staining techniques? - Presence of chloroplasts - Density of membrane folds in mitochondria - # of virus particles infecting an animal cell - Type of cell wall of a bacterium - Relative size of a central vacuole

- Presence of chloroplasts - Relative size of a central vacuole

Which of the following would be scientific evidence to support the Cell Theory? - the first cells on Earth may have arisen through abiogenesis - viruses have membranes, proteins, and nucleic acids - all living organisms undergo metabolic processes and maintain homeostasis - all known plants are made of cells

- all known plants are made of cells

Approximately, what is the smallest size that the human eye can resolve?

0.1 mm

Arrange the following from smallest to largest (in diameter) - Bacteria cell - Fungus cell - Human lung cell - 1 nanometer - Virus that infects human cells

1 nm, Virus, bacteria cell, Fungus cell, Human lung cell

Theodor Schwann developed Cell Theory which had two basic principles which were:

1. All organisms consist of one or more cells. 2. The cell is the basic unit structure for all organisms. Virchow added a third principle which was? 3. All cells arise only from preexisting cells.

Traditional eukaryotic organelles are bound by a (lipid) membrane. These include:

1. Nucleus 2. endoplasmic reticulum 3. Golgi complex 4. mitochondrion 5. vesicle 6. peroxisome - Lysosome (animals) - Chloroplasts (plants and algae) - Central vacuole (some plants)

Assuming the shape remains the same, a 10-fold increase in diameter results in a cell that is:

1000 larger by volume

scanning electron microscope

An electron microscope used to study the fine details of cell surfaces

What two kingdoms are prokaryotes?

Bacteria and Archaea

An organism may be considered to be alive if it or its parts display the characteristics of life which include:

Characteristics of Life: •"Self" reproduce (sexually or asexually) and pass on traits (heredity) •Maintain homeostasis and respond to environmental stimuli •Develop and undergo metabolic processes Be defined by and composed of discrete structures

Photosynthetic bacteria contain chloroplasts.

False

To be ALIVE means:

GRR CHHM: (Grr chum) - Growth & development - Reproduce (offspring) - Respond to the environment - Cellular structures & composition - Heredity of traits - Homeostasis (stable inner conditions) - Metabolism (energy from chemical rxns)

What was the first metabolic pathway on Earth?

Photosynthesis

Which of the following statements is thought to be true? - Unicellular eukaryotes evolved before prokaryotes - Photosynthesis first evolved in prokaryotes - Mitochondria evolved after chloroplasts - All of the above are true

Photosynthesis first evolved in prokaryotes

What are the six kingdoms?

Plants, Animals, Protists, Fungi, Archaea, and Bacteria

Briefly explain why comparing rRNA is better (more accurate) than using genomic DNA sequences when attempting to distinguishing the different domains of life.

Ribosomal RNA sequences differ between species, due to mutation. Through variation in rRNA sequences we can distinguish organisms on approximately the species level and trace evolutionary relationships.

Who coined the term "cells"?

Robert Hooke b/c the structures in cork that he observed with his microscope resembled the cells of a honeycomb

What type of microscopy image is shown below? (Surface image of cell, where only outer surface is captured in black and white)

Scanning electron

How did the microscope contribute to the development of the Cell Theory?

The microscope made it possible to see cells because it gave conclusions and observations to the cell theory

What is the Endosymbiont Theory?

Theory posits that mitochondria and chloroplasts descended from ancient prokaryotes that were engulfed by eukaryotic cells The engulfed organism and the host cell developed a symbiotic relationship where the mitochondria could focus on energy-making processes while the rest of the cell thrived

Saccharomyces cerevisiae do not contain chloroplasts.

True

What is Cell Theory?

all living cells are formed by the growth and division of existing cells

How are mitochondria and chloroplasts similar?

both have DNA and are surrounded by a double membrane also have ribosomes to make their own proteins

The Nucleus contains:

contains DNA and has several specialized structures

How did the first cells evolve into modern-day cells?

eventually, eukaryotes (larger cells) could no longer live off of just fermentation and they needed more energy which lead to the evolution of metabolic processes of energy making like cellular respiration

Rough ER is where:

protein synthesis occurs

single celled eukaryotes

protists/protozoa

The nucleotide sequences of which of the following have been used to create a single all-encompassing tree of life?

rRNA gene

Cytoskeleton:

structural support, elasticity, cell movement, intracellular transport, cell division, and organelle localization.

Model organisms are used to study:

study conditions and processes that are applicable to humans

What is cell biology?

the study of cells and their structure, function, and behavior

Smooth ER is involved in:

the synthesis of lipids and stores calcium

Characteristics of Bacteria include:

• Smallest, "simplest" cells • Divide rapidly • Evolve quickly • Any species can have many different strains Examples of bacteria: E. coli, C. diff, MRSA

Characteristics of Archaea include that they:

• Tend to live in extreme conditions • Thought to more related to eukaryotes that bacteria Types of archaea include: • Thermophiles: "Heat- loving"; Live in hot springs. • Halophiles: "Salt-loving"; Occupy extremely salty environments. • Methanogens: Convert CO2 into CH4 in the gut

All living cells:

•Are enclosed in a membrane •Store hereditary information (in nucleic acid sequence) •Undergo metabolic processes ◦(This is what helps determine if a cell is alive or not)

Exceptions to Cell Theory:

•The first living cell(s). •Man-made synthetic cells Life elsewhere in the universe

"Life-like particles" are:

•discrete, replicating, acellular infectious agents, that lack some of the characteristics of life

Mitochondria:

•make ATP •Site of aerobic respiration •Found in all eukaryotic cells •Comparable in size to bacteria

What are 5 pieces of evidence for endosymbiosis (like bacteria, mitochondria, and chloroplasts)?

1. Are bound by double membranes, the inner of which has bacterial- type lipids [Chloroplasts actually have a third membrane system] 2. Contain their own DNA and ribosomes 3. Have similar ribosomal properties (rRNA sequences, sizes, sensitivities to inhibitors) 4. Have circular DNA molecules (without histones) 5. Reproduce via fission

Name at least four model organisms and what they are used for.

1. Mice: genetically and physiologically similar to humans than many other model organisms, they are often used to study human diseases. 2. Yeast: cheap to grow and maintain, carries out all the basic tasks that a eukary cell must perform grow and reproduce rapidly allowing for many generations to occur in a relatively small amount of time 3. Fruit fly: they are easy and inexpensive to grow and maintain in the lab, have a short life cycle of 8 to 14 days, and produce a large number of offspring that are laid externally

Only certain species are used as model organisms. They have several characteristics that make the particularly suitable for experimentation. These include:

1. Pre-existing knowledge of the organism's biological properties 2. Transferability of information (how relevant is it to other organisms of interest) 3. Affordability and availability •Ease of and adaptability to experimental manipulation 4. Generation time and size (life span and reproducibility) 5. Ethical implications

Theories on the origins of membrane-enclosed compartments tend to center on two hypothesis:

1. The Endomembrane System 2. The Endosymbiont Theory

Rickettsia:

1. are obligate intracellular parasites 2. Cause a variety of human diseases, such as typhus and Rocky Mountain spotted fever. Rickettsia are transmitted to humans through bites from ticks, fleas, and lice 3. •These bacteria rely on a host eukaryotic cell in order to survive. •Are capable of producing their own ATP, but unlike other bacteria, contain no genes for anaerobic glycolysis. •Relies on the metabolic pathways of host cells for many essential molecules. Must be living inside a host cell in order to replicate

Which statement is not true of E. coli? A. E. coli is a model eukaryote. B. E. coli can be grown in the laboratory. C. E. coli normally lives in the gut of humans and other vertebrates. D. E. coli is a small, rod-shaped cell. E. E. coli stores genetic information in the form of DNA.

A. E. coli is a model eukaryote.

transmission electron microscope

An electron microscope used to study the internal structure of thin sections of cells

Which of the following cell types contains a cell wall? - Animal - Archaea - Bacteria - Fungi - Plant

Archaea Bacteria Fungi Plant

You are trying to help a friend categorize a unicellular organism. All your friend tells you is that the organism appears blue-green, has a cell wall, and undergoes photosynthesis. Based on just this info, to what kingdom may this organism belong?

Bacteria or protist

What are the three domains?

Bacteria, Archaea, Eukarya

What role is NOT performed by the cytoskeleton? A. Pulling duplicated chromosomes to opposite poles in dividing cells B. Transporting organelles and molecules from one place to another in the cytoplasm C. Generating chemical energy D. Controlling cell shape and cell movement E. Generating contraction in muscle cells

C. Generating chemical energy

Eukaryotic cells have specialized mechanisms to overcome some of the limitations of diffusion. How do Carrier Proteins, Cytoplasmic streaming, and Vesicles play a role in this?

Carrier proteins actively transport ions and macromolecules through the cytoplasm Cytoplasmic streaming actively move and mix cytoplasmic contents Vesicles in which specific molecules are endo/exocytose, and transported along microtubules

Antibiotics tend to target features that are unique to bacterial cells and absent from eukaryotic cells such as our own. Which of the following would present a safe target for a new antibiotic? - nuclear envelope - intermediate filaments - plasma membrane - cell wall - endoplasmic reticulum

Cell Wall

The Nuclear Envelope:

Consists of two, concentric membranes; the outer membrane is contiguous with the ER Nuclear pores help regulates transport in and out of nucleus

Which of the following is a model plant used by scientists? A. Caenorhabditis elegans B. Saccharomyces cerevisiae C. Homo floresiensis D. Arabidopsis thaliana E. Homo sapiens

D. Arabidopsis thaliana

The Nucleolus:

Dense area where rRNA is transcribed and ribosome assembly is initiated; ~25% of nuclear volume

Peroxisomes:

Detoxify and catabolize harmful compounds and unusual substances

Life vs. Cells vs. NOT

LIFE: Cells, the fundamental unit of life, are bound by discrete structures, contain hereditary material and undergo metabolic processes. NOT: Viruses rely on the metabolic processes of cells in order to replicate.

You are a biologist interested in studying how eukaryotic cells obtained their unique features during their evolution from a prokaryotic ancestor. Which cellular features, unique to eukaryotes, might you focus on? (Select all that apply) - mitochondria - ribosomes - cell membrane - nucleus

Mitochondria and Nucleus

Which is not evidence for the endosymbiotic origins of mitochondria and chloroplasts? Mitochondria and chloroplasts resemble bacteria. Mitochondria and chloroplasts contain their own DNA. Mitochondria and chloroplasts have similar DNA. Mitochondria and chloroplasts are each surrounded by a double membrane. Mitochondria and chloroplasts reproduce by dividing in two.

Mitochondria and chloroplasts have similar DNA.

What are microcompartments where specific functions are carried out?

Organelles

Starting in the 1600's, several developments helped spawn the discipline of cell biology:

Spontaneous generation was experimentally disproved. Advancements in microscopy allowed for viewing of single cells.

Why can prokaryotic cells be divided into the widely divergent Bacteria and Archaea?

based on rRNA sequence analysis

Both viruses and Rickettsia rely on the metabolic pathways of host cells, and need a host for replication. Can you think of reasons why Rickettsia have been classified as bacteria whereas viruses are life-like particles?

because they are spread by biological vectors like ticks, fleas, and lice Rickettsia also possess a true cell wall

Ribosomes:

catalysts for protein synthesis located on ER or in the cytoplasm are made of a large and small subunit can only be seen under electron microscope

Extracellular Matrix

cellular integrity/structure, cell-cell recognition, adhesion, signaling, and defense

In order to stay alive, thrive and propagate, all cells need...

chemical catalysts, such as enzymes information to drive processes, such as DNA oxygen

Antonie van Leeuwenhoek (1632-1723)

first to observe living microbes, single-lens magnified up to 300X "animalcules" - rainwater, his own feces and semen first reports of protozoa and bacteria

Viruses are:

genome-containing, parasitic particles that replicate using host cells' machinery (enzymes, etc)

What is the central dogma?

in all living cells, genetic information flows from DNA to RNA (via transcription) and from RNA to protein (via translation); an arrangement known as the central dogma

Prior to the "discovery" of cells, many theories postulated that life arose from:

inanimate matter via spontaneous generation Ex: Recipe for Mice dirty shirt(s) + wheat + 21 days = MICE

When did life arise on Earth?

life first appeared on Earth ~ 3.8 billion years ago

What cellular structures are visible via light microscopy?

light microscopes allow one to visualize cells and their larger components such as nuclei, nucleoli, secretory granules, lysosomes, and large mitochondria

Which of the following microscopy techniques was used by the scientists that studied and described cells in the 1600-1800s? - electron microscopy - light microscopy - fluorescence - all of the above

light microscopy

Which of the following is a small, irregularly shaped organelle in which intracellular digestion occurs? - Golgi complex - lysosome - ribosome - ER - peroxisome

lysosome

Robert Brown identified the:

nucleus (a structure inside plant cells he saw)

Lysosomes

organelle where biological molecules are broken down by digestive enzymes, hydrolases

What is a melanosome?

pigment storage in some animal cells, such as in the skin

The Golgi Complex:

plays an important role in processing and packaging secretory proteins, and in complex polysaccharide synthesis

What is an eye spot?

sense light for phototaxis; found in green algae and some protists

fluorescence microscopy

shows the locations of specific molecules in the cell

The defining characteristic of a eukaryotic organism is:

the presence of a nucleus

the scanning electron microscope—scatters electrons off the surface of the sample and so is used to look at:

the surface detail of cells and other structures

The fine structure of a cell can be seen in a:

transmission electron microscope it transmits a beam of electrons rather than a beam of light through the sample

What is the Endomembrane System Theory?

was the result of infoldings of the plasma membrane (The endomembrane system is composed of the different membranes that are suspended in the cytoplasm within a eukaryotic cell. These membranes divide the cell into functional and structural compartments, or organelles)

Which organism would be the most useful for studying how mutations that cause sudden death in young athletes can affect the development of the heart?

zebrafish

Chloroplasts

•synthesize glucose - Photosynthesis occurs in the thylakoids (third membrane) •Found in plants and algae •Very large cellular organelle

What are 3 facts about viruses?

◦Contain outer membranes/coats, and internal nucleic acids ◦Do not have metabolic processes. Incapable of a free-living existence