Exam 1 Eukaryotes

Robert Hooke

1665; English microbiologist; first to describe cell; termed the pores inside corks cells because they reminded him of cells occupied by monks living in a monastery

Anton van Leeuwenhoek

1665-1675; Dutch; first to describe living single cells; examine a drop of pond water and observe microscopic 'animalcules’

Matthias Schleiden

1838; botanist; claimed all plant tissues composed of cells; described how plant embryos arise from a single cell; helped articulate the cell theory

Theodo Schwann

1839; zoologist; claimed all animal tissues composed of cells; helped articulate the cell theory

Rudolf Virchow

1855; German pathologist; added 3rd tenet of cell theory

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

added to cell theory:

cells contain genetic information (DNA) passed to the next cell generation

HeLa cells

cultured tumor cells isolated from Henrietta Lacks, a cancer patient

basic properties of cells:

1. cells are highly complex and organized

2. cells possess a genetic program and the means to use it

3. cells are capable of producing more of themselves

4. cells acquire and utilize energy to maintain complexity

5. cells carry out a variety of chemical reactions

6. cells engage in mechanical activities

7. cells are able to respond to stimuli

8. cells are capable of self-regulation

9. cells evolve

Cells arise by division of preexisting cells

Which of the following statements about cell theory is true?

HeLa cells

What is the name of the first immortalized cell isolated from a cancer patient?

two different classes of cells:

prokaryotes and eukaryotes

prokaryotes

structurally simpler; bacteria and archaea

eukaryotes

structurally more complex; protists, fungi, plants, and animals

common features of prokaryotes and eukaryotes:

bound by plasma membrane, may have cell wall, genetic material, transcription and translation, shared metabolic pathways, similar apparatus for conversion of chemical energy, similar photosynthesis, proteasome of similar structure, cytoskeletal filaments

prokaryote chromosome structure:

single, circular chromosome of DNA

eukaryote chromosome structure:

numerous chromosomes, contain linear DNA

characteristics that distinguish prokaryotic and eukaryotic cells:

eukaryotes have membrane-bound organelles, cellular reproduction, flagella form and mechanism

binary fission

prokaryotes; proliferate faster

eukaryotic organelles

organelles divided the cytoplasm into compartments within which specialized activities take place

features of eukaryotic cells not found in prokaryotes:

nuclear envelope, complex chromosomes, complex membranous cytoplasmic organelles, specialized cytoskeletal system and associated motor proteins, complex flagella and cilia, phagocytosis, mitotic spindle, diploidy, 3 different RNA polymerases, sexual reproduction requiring meiosis and fertilization

single large vacuole

found in plant cells, occupies most of the cell volume

lysosomes

contain hydrolytic enzymes and carry out hydrolytic gestation

peroxisomes

organelles that sequester diverse oxidative reactions

glyoxysomes

plant peroxisomes

conjugation

process by which one bacterium transfers genetic material to another through direct contact

prokaryotes have remained on Earth for _______.

several billion years

methanogens

capable of converting CO2 and H2 gases into methane (CH4) gas

halophiles

live in extremely salty environments like the Dead Sea

acidophiles

acid-loving prokaryotes that thrive at pH as low as 0

thermophiles

live at very high temperatures

hyperthermophiles

live in hydrothermal vents of the ocean floor up to a temperature of 121 C

nitrogen fixation

N2 —> ammonia

metagenome

recovery and complete sequencing of genetic material extracted directly from all environmental samples

human microbiome

collection of microbes living on us and in us

differentiation

formation of specialized cells

E. coli

bacteria model organism

Saccharomycese cerevisiae

a budding yeast; single-celled model organism of eukaryotes

Arabidopsis thaliana

mustard plant; a flowering plant model organism

Caenorhabditis elegans

a nematode; model organism

Mus musculus

a mouse; model organism

viruses

obligatory intracellular parasites; must reproduce in host cells

virion

virus particle outside the host cell; contains genetic material plus protein subunits

bacteriophages

viruses that infect bacteria

viroids

infectious agent; small, circular RNA lacking a protein coat

adenovirus

HPV leads to cervical cancer

Human immunodeficiency virus

AIDS; an RNA virus

Cadang Cadang

devastated coconut palm groves of the Philippines

viroid traits

1. RNAs range from 240-600 nucleotides

2. duplication of viroid RNA uses host enzymes and proteins

3. viroid RNA does not code for proteins

stem cell

not specialized and can give rise to more stem cells or specialized cells

viral specificity for a certain host is determined by the ___________.

virus’ surface proteins, since interaction requires those proteins to bind surface proteins of the host cell

lytic infection

virus redirects the host into making more virus particles, the host cell lyses and releases the viruses

integration

virus integrates its DNA (called a provirus) into the host cell’s chromosomes

nuclear envelope

Prokaryotic cells can be distinguished from eukaryotic cells by the absence of:

Archaea

Which group of prokaryotes is best known for containing many extremophiles?

An organism is composed of more than one cell

Which of the following is NOT one of the tenets of the cell theory?

ATP

What molecule do animal cells use to store readily available energy?

Cells are simple and unorganized

Which of the following is NOT a basic property of cells?

You can measure the amount of DNA present in the solution. If there is less than 8,000 Mb of DNA, the cell is most likely prokaryotic

You are studying a cell that has ruptured and your professor asks you to determine whether the cell is prokaryotic or eukaryotic. Which of the following ways can you use to determine the class of the cell?

You see a patient that is not showing any symptoms of disease, but when you analyze their DNA, you notice viral DNA integrated into the host genome. What type of infection is this?

integration

Prokaryotes can incorporate foreign DNA from their environment, allowing them to evolve quickly.

Which of the following explains why evolution can occur rapidly in prokaryotes?

Halophiles

You are a biologist working out in the field and take a sample from the Red Sea, which contains a high concentration of salt. Which Archaea would you most likely find in this sample?

Differentiation

What process allows multicellular eukaryotes to form specialized cells with different functions?

conjugation

Some bacteria can pass a piece of DNA from a donor bacterial cell to a recipient bacterial cell through a structure called a plus. What is this process called?

proteasome

Which organelle is found in both eukaryotes and prokaryotes?

hydrogen bonds

What bonds hold together strands of DNA?

van Der Waals Forces

instantaneous dipoles formed as a result of the distribution of electrons on one end of a molecule, which can then induce an instantaneous dipole on the adjacent molecule; very weak intermolecular forces

important characteristics of the water molecule:

1. bent

2. highly polarized

3. all three molecules can form hydrogen bonds

How can the weak van Der Waals forces be maximized?

when two molecules have complimentary surfaces, allowing them to form numerous van Der Waals interactions

why does water have a high boiling point?

water molecules form numerous hydrogen bonds (up to 4) with other water molecules, meaning that a lot of energy is needed to break these bonds

covalent bonds

atoms share electrons to form bond

strong covalent bonds

energy required to break is much greater than thermal energy

weak covalent bonds

energy required to break is the same or smaller than thermal energy

polar molecules

molecules with an asymmetric distribution of charge

non polar

molecules that lack electronegative atoms and strongly polarized bonds; includes fats

acids

release (donate) protons

bases

accept protons

amphoteric molecules

can act as either acid or base molecules

dehydration synthesis

process of removing water to form covalent bonds; forms growing polymers

hydrolysis

process of using energy, enzymes, and water to cleave bonds between polymers; opposite of dehydration synthesis

buffers

compounds (weak acid and its conjugate base) that help to resist pH changes

biochemicals

compounds produced by living organisms

ester bonds

between carboxylic acids and alcohols

amide bonds

between carboxylic acids and amines

What is the least abundant macromolecule in the body?

nucleic acids followed by polysaccharides

What is the most abundant macromolecule in the body?

proteins

macromolecules

highly organized molecules; can be divided into proteins, nucleic acids, polysaccharides, and certain lipids

functions of biological molecules:

1. macromolecules

2. building blocks of macromolecules

3. metabolic intermediates (metabolites)

4. molecules of miscellaneous function

metabolites

compounds formed along metabolic pathways that might have no function per se; intermediates in a reaction

molecules of miscellaneous function

vitamins, certain steroid or amino acid hormones, ATP, cyclic AMP ( regulatory molecules) and urea (waste)

rhizobia

bacteria that fix nitrogen

What is the term for specific arrangements of atoms that commonly act as a cohesive unit, influencing the physical properties, chemical reactivity, and solubility of organic molecules in aqueous solutions?

functional groups

4 major categories of macromolecules:

proteins, nucleic acids, polysaccharides, lipids

sugars

precursors of polysaccharides

amino acids

precursors of proteins

nucleotides

precursors of nucleic acids

fatty acids

incorporated into lipids

carbohydrates

simple sugars and all larger molecules constructed of sugar building blocks

carbohydrates function:

stores of chemical energy and durable building materials for biological construction

general formula for a carbohydrate:

(CH2O)n