Cell Biology 2131: Chapter 1 - Introduction to Cell Biology (Karp 8e)

Cell research focuses on six model organisms.

These are the bacterium _, the yeast_, the mustard plant _, the nematode _, the fruit fly _, and the mouse _.

Escherichia coli

Saccharomyces

Arabidopsis

Caenorhabditis elegans

Drosophila

Mus musculus

200 years later

1830s Full & widespread of importance of cells realized

Matthias Schleiden

Botanist (1838) claimed all plant tissues composed of cells; described how plant embryos arise from a single cell

Cell Theory

1. All organisms are composed of one or more cells

2. The cell is the structural unit of life for all organisms

3. Cells can arise only by division from a preexisting cell.

Basic Property of Cells

Life - Cells are the smallest units to exhibit life; plant and animal cells when removed from organism can live in culture in laboratory

Basic property of Cells

Cells are highly complex and organized

Basic property of cells

Cells have complex metabolism - many chemical reactions using enzymes which are molecules that great increase rate of chemical reactions

Pro

before

Karyon

nucleus

Similarities between prokaryotes & eukaryotes

a. both types of cells contain same type of DNA (genetic language)

b. both types of cells share a common set of metabolic pathways

c. both types of cells share common structural features - e.g cell membrane

Prokaryotes DNA length

Relatively little DNA (0.25 - ~3mm) coding for several hundred to several thousand proteins

Eukaryotes DNA length

Simplest eukaryotes (4.6 mm in yeast encoding ~6200 proteins) have slightly more DNA than prokaryotes; most eukaryotes have an order of magnitude more DNA.

Eukaryote chromosome structure

Eukaryotic chromosomes numerous; contain linear DNA

Locomotion

Eukaryotes have more complex locomotion. prokaryotes have rotating flagella; eukaryotes have more complex flagella with different mechanism and also may have cilia & pseudopodia.

Necrosis

When cell is unable to switch into the apoptosis stage

Halophiles

Live in extremely salty environments (Dead Sea & Great Salt Lake)

Bacteriophage

Infects bacteria

Adenovirus

HPV leads to cervical cancer

Viroid traits

1. RNAs range from about 240 to 600 nucleotides (10% size of smaller viruses)

2. Duplication of viroid RNA uses host enzymes & proteins

3. Viroid RNA does not code for proteins; may case disease by interfering with cell's normal path of gene expression

What do all viruses consist of?

Viral nucleic acid wrapped in a capsid (viral proteins)

Which of the following is a NON-covalent bond?

1. dipole-dipole

2. H-bond

3. London dispersion forces

4. Ionic bonds

Nucleic acids are composed of what 3 things?

1. a base

2. a phosphate group

3. a ribose

muscle pain that occurs during running is caused by _

build up of lactic acid (due to lack of oxygen built up in muscle tissue; ATP has been used up)

3 steps of cellular respiration - gives cells the means to make ATP

glycolysis

Krebs cycle

oxidative phosphorylation

Cells Possess a _and the Means to Use It

Genes encode info to _ each cell & the organism & for cellular _, _ & _

genetic program

build

reproduction, activity & structure

Cells are capable of producing what?

more of themselves

Cell reproduce & each daughter cell receives a complete set of genetic instructions

Mitosis results in _ while meiosis results in _

two diploid daughter cells (2n-> 2n + 2n)

^genetically identical

four haploid cells (2n-> 1n + 1n + 1n + 1n)

^increases the potential for genetic diversity

In what kind of cells would we see meiosis?

Germ cells (somatic cells reproduce by mitosis)

sperm (1n) + egg (1n) = _

zygote (2n)

Cells acquire & utilize energy:

_provides fuel for all living organisms.

Animal cells derive energy from the products of _, mainly in the form of _.

Cell can convert glucose into _—a substance with readily available energy.

Photosynthesis

photosynthesis / glucose

ATP

first law of thermodynamics

Energy can neither be created nor destroyed, only its form can be changed

taking one form of energy and changing it to another form of energy

energy transformation (relates to energy flow through all living things, including metabolism)

Cells Acquire and Utilize _

Cells Carry Out a Variety of _

Cells Engage in _

Cells Are Able to Respond to _

Cells are capable of _

Cells _

energy

chemical reactions

mechanical activities

stimuli

self-regulation

evolve

cancer cells of an epithelial origin

carcinoma

DNA duplication occurs with an error rate of less than _

one mistake every 10 million nucleotides incorporated - & most are quickly corrected

The epithelial cells lining the intestine are tightly connected to each other. Their _ ends, which face the intestinal channel, have long processes (_) that facilitate absorption of nutrients

apical

microvilli

Microvilli are able to project outward from the apical cell surface because they contain an _ made of _ which are in turn composed of _

internal skeleton made of filaments which are in turn composed of actin (protein)

Changes in genetic information (_) form the basis of biological evolution

mutations

Virtually all the energy utilized by life on Earth's surface arrives in the form of _ from the _

electromagnetic radiation from the sun

Light energy is converted by _ into _ that is stored in energy-rich carbohydrates such as _ or _. For most animals, energy arrives prepackaged, often in the form of the _.

photosynthesis / chemical energy

sucrose or starch

glucose

In humans, glucose is released by the _ into the _ where it circulates through the body delivering _ to all the cells.

liver / blood / chemical energy

Virtually all chemical changes that take place in cells require _.

enzymes: molecules that greatly increase the rate of chemical reactions

sum total of chemical reactions in a cell

cellular metabolism

A cell's mechanical activities are based on dynamic, mechanical changes within cells that are initiated by changes in what?

the shape of "motor" proteins

Most cells are covered with _ that interact with substances in the environment in very specific ways

receptors

A cell's receptors provide pathways through which external stimuli can evoke specific responses in target cells.

Cells are _, that is hearty or durable, because they are protected from dangerous fluctuations in composition & behavior

robust

In cells, the information for design resides in _ & the construction workers are primarily _

nucleic acids

proteins

Cells present in living organisms share many features, including:

common genetic code, plasma membrane & ribosomes

All living organisms evolved from a single, common ancestral cell that lived more than _ yrs ago. Because it gave rise to all living organisms that we know of, this ancient cell is often referred to as _

3 billion

LUCA (last universal common ancestor)

The 2 basic classes of cells (_&_) are distinguished by their _ & type of internal structures (_). The structurally simpler _ cells include bacteria, whereas the structurally more complex _ cells include protists, fungi, plants & animals

prokaryotic & eukaryotic

size / organelles

prokaryotic

eukaryotic

Evidence of prokaryotic life has been obtained by rocks approximately _ years old

2.7 billion

without the involvement of living cells

abiotically

Cyanobacteria almost certainly appeared by _ years ago, because that is when the atmosphere became infused with _, which is a byproduct of the _ activity of these prokaryotes

2.4 billion years ago

O2 (molecular oxygen): byproduct of photosynthetic activity

Shared properties of prokaryotes & eukaryotes

plasma membrane & cell wall

Genetic material of a prokaryotic cell is present in a _: a poorly demarcated region of the cell that lacks a boundary membrane to separate it from the surrounding cytoplasm.

nucleoid

Eukaroytic cells possess a _ which contains its genetic material

nucleus (a region bound by a complex membraneous strutter called the nuclear envelope)

Nearly all prokaryotes contain how many chromosomes?

a single, circular chromosome

The chromosomal DNA of eukaryotes, unlike prokaryotes, is tightly associated with proteins to form a complex nucleoprotein material known as _

chromatin

where chemical energy is made available to fuel cellular activities

mitochondria

where many of a cell's proteins & lipids are manufactured

endoplasmic reticulum

where materials are sorted, modified, and transported to specific cellular destinatinos

Golgi complexes

sites of photosynthesis

chloroplast

occupies most of the volume of the cell

vacuole

Though most prokaryotes are essentially devoid of membraneous structures, the complex photosynthetic membranes of the _ are a major exception

cyanobacteria

Eukaryotes also contain structures lacking an external membrane:

tubules & filaments of the cytoskeleton

Both eukaryotes & prokaryotes contain _, the nonmembraneous particles where proteins are manufactured

ribosomes

soluble phase of cytoplasm

cytosol

Eukaryotic cells divide by mitosis, in which duplicated chromosomes condense into compact structures that are segregated by _

mitotic spindle (an elaborate microtubule-containing apparatus)

Though prokaryotes lack true sexual reproduction, some are capable of _, in which a piece of DNA is passed from one cell to the other

conjugation

The movement of prokaryotic cells may be accomplished by a thing protein filament (_) which protrudes from the cell & rotates. Certain eukaryotes such as protists & sperm cells also contain these.

flagellum

Many prokaryotes live in complex, multi species communities called _

biofilms

Prokaryotes are divided into 2 major taxonomic groups/domains:

Archaea & Bacteria

The best known Archaea (_) live in extremely inhospitable environments. 3 types:

can convert CO2 & H2 into CH4

can live in extremely salty environments

can live in very acidic conditions

can live at very high temps

extremophiles:

methanogens

halophiles

acidophiles

thermophiles

The smallest known cells (_), part of domain Bacteria, are the only known prokaryotes to lack a cell wall & to contain a genome with less than 500 genes

mycoplasma

The most complex prokaryotes (_) contain elaborate arrays of cytoplasmic membranes, which serve as sites of photosynthesis

cyanobacteria

conversion of nitrogen (N2) gas into reduced forms of nitrogen that can be used by cells in the synthesis of nitrogen-containing organic compounds, including amino acids & nucleotides

nitrogen fixation

The basis of biological evolution: though all organisms may share genes, the _ that make up the genes varies considerably from one species to another

sequences of nucleotides that make up the genes

all the genes present in the microbes of a given habitat can be sequenced, generating a collective genome (_)

metagenome

Collection of microbes that live on or within our own bodies (such as intestinal tract, vagina, mouth & skin)

microbiome

The most complex eukaryotic cells are found amongst _

unicellular protists

specialized cells are formed by a process called _

differentiation

DNA is approximately _ in width

2nm

3 reasons cells are so small

Most eukaryotic cells contain a single nucleus that contains only 2 copies of each gene

As a cell increases in size, the surface area/volume ratio decreases

A cell depends on the random movement of molecules (diffusion). The time required for diffusion is proportional to the square of the distance traversed

Biological research centered on creating some minimal type of living cell in the laboratory from "scratch"

synthetic biology

Many human diseases result from the death of _.

_ is most often used to treat lymphomas & luekemias, cancers which affect the nature & # of white blood cells.

specific types of cells

bone marrow transplantation

blood-forming cells in the bone marrow, responsible for replacing millions of red & white blood cells that age & die every minute in our bodies

hematopoietic stem cells (HSCs), an example of an adult stem cell

undifferentiated cells that are capable of self-renewal (production of more cells like themselves) & are multi-potent(capable of differentiating into two or more mature cell types)

stem cells

supportive cells of the brain

glial cells

treatment in which cells are taken from the same patient in which they are used

autologous

Benefit of autologous treatment

The patient is not at risk of immune rejection

stem cell isolated from a very young mammalian embryo; gives rise to all the various structures in the mammalian fetus (pluripotent)

embryonic stem (ES) cell

capable of differentiating into every type of cell in the body

pluripotent

cells that produce myelin sheaths that become wrapped around nerve cells

oligodendrocytes

may contain a bizarre mass of various differentiated tissues, including hair & teeth

teratoma

It may be possible to customize embryonic stem cells so that they possess the same genetic makeup as the individual being treated, via a procedure called _, in which the nucleus of the unfertilized egg is replaced by the nucleus of a cell from the patient to be treated, causing the egg to have the same chromosome composition of the patient

somatic cell nuclear transfer (SCNT)

Induced pluripotent cells (iPS cells) were created by introducing _ into a mouse fibroblast

the genes that encode the 4 key proteins characteristic of ES cells: OSKM, thought to play a key role in maintaining cells in an undifferentiated state, allowing them to continue self-renewal

Unlike ES cells, the generation of iPS cells does not require use of an _. Like ES cells, undifferentiated iPS cells also give rise to _

embryo

teratomas

converting one type of differentiated cell into another type of differentiated cell

transdifferentiation

_ concluded that certain diseases are caused by pathogens smaller & simpler than the smallest known bacteria. These pathogens became known as _.

Ivanovksy

viruses

rod-shaped particle consisting of a single molecule of RNA surrounded by a helical shell composed of protein subunits

tobacco mosaic virus (TMV)