Chpt. 1

Question 1

Cell Theory

Answer 1

1. All living things are composed of cells
2. The cell is the basic functional unit of life.
3. Cells arise only from preexisting cells.
4. Cells carry genetic information in the form of DNA. This genetic material is passed on from parent to daughter cell.

Question 2

Eukaryote

Answer 2

have membrane-bound organelles, a nucleus, and may form multicellular organisms.

Question 3

Cell membrane and organelle membrane

Answer 3

contain phospholipids, which organize to form hydrophilic interior and exterior surfaces with a hydrophobic core.

Question 4

Cytosol

Answer 4

suspends the organelles and allows diffusion of molecules throughout the cell

Question 5

Nucleus

Answer 5

contains DNA organized into chromosomes. It is surrounded by the nuclear membrane or envelope, a double membrane that contains nuclear pores for two-way exchange of materials between the nucleus and cytosol. DNA is organized into coding regions called genes.

Question 6

Nucleolus

Answer 6

subsection of nucleus in which ribosomal RNA is synthesized

Question 7

Mitochondria

Answer 7

contains inner and outer membrane. Outer membrane forms barrier with the cytosol; inner membrane is folded into cristae and contains enzyme for the electron transport chain. Between the membranes is the intermembrane space; inside the inner mitochondrial membrane is the mitrochondrial matrix. Mitochondria can divide independently of the nucleus via binary fission and can trigger apoptosis by releasing mitochondrial enzymes into the cytoplasm.

Question 8

Lysosomes

Answer 8

contain hydrolytic enzymes that can break down substances ingested by endocytosis and cellular waster products. When these enzymes are released, autolysis of the cell can occur.

Question 9

Endoplasmic reticulum (ER)

Answer 9

a series of interconnected membranes and is continuous with the nuclear envelope. The rough ER (RER) is studded with ribosomes, which permit translation of proteins destined for secretion. The smooth ER (SER) is used for lipid synthesis and detoxification.

Question 10

Golgi apparatis

Answer 10

consists of stacked membrane-bound sacs in which cellular products can be modified, packaged, and directed to specific cellular locations

Question 11

Peroxisomes

Answer 11

contains hydrogen peroxide and can break down very long chain fatty acids via B-oxidation. They also participate in phospholipid synthesis and the pentose phosphate pathway.

Question 12

Cytoskeleton

Answer 12

provides stability and rigidity to the overall structure of the cell, while also providing transport pathways for molecules within the cell

Question 13

Microfilaments

Answer 13

composed of actin. Provide structural protection for the cell and can cause muscle contraction through interactions with myosin. They also help form the cleavage furrow during cytokinesis in mitosis.

Question 14

microtubules

Answer 14

composed of tubulin. Create pathways for motro proteins like kinesin and dynein to carry vesicles. They also contribute to the structure of cilia and flagella, where they are organized into nine pairs of microtubules in a ring with two microtubules at the center (9+2 structure). Centrioles are found in centrosomes and are involved in microtubule organization in the mitotic spindle.

Question 15

Intermediate filaments

Answer 15

are involved in cell-cell adhesion and maintenance of the integrity of the cytoskeleton; they help anchor organelles. Common examples include keratin and desmin.

Question 16

Epithelial Tissue

Answer 16

cover the body and line its cavities, protecting against pathogen invasion and desiccation. Some epithelial cells absorb or secrete substances, or participate in sensation. May be polarized, with one side facing a lumen or the outside world, and the other side facing blood vessels and structural cells.

Question 17

Parenchyma

Answer 17

formed by epithelial cells in most organs.

Question 18

Epithelia layers

Answer 18

simple epithelia - have one layer
stratified epithelia - have many layers
pseudostratified epithelia - appear to have many layers dues to difference in cell heights, but actually have only one layer.

Question 19

Epithelia shapes

Answer 19

cuboidal cells - cube shaped
columnar cells - long and narrow
squamous cells - flat and scale-like

Question 20

Connective tissues

Answer 20

support the body and provide a framework for epithelial cells.

In most organs, connective tissues form the stroma or support structure by secreting material to form an extracellular matrix.

Ex. bone, cartilage, tendons, ligaments, adipose tissues, and blood

Question 21

Prokaryotes

Answer 21

do not contain membrane-bound organelles; they contain their genetic material in a single circular molecule of DNA located in the nucleoid region.

Prokaryotes carry out the electron transport chain using the cell membrane

Prokaryotic ribosomes are smaller than eukaryotic ribosomes(30S and 50S, rather than 40S and 50S)

Question 22

Archaea

Answer 22

often extremophiles, living in harsh environments and often use chemical sources of energy (chemosynthesis) rather than light. They have similarities to eukaryotes(start translation with methionine, similar RNA polymerases, histones) and bacteria (single circular chromosomes, divide by binary fission or budding)

Question 23

Eukarya

Answer 23

the only non-prokaryotic domain

Question 24

Bacteria

Answer 24

have similar structures to eukaryotes, and have complex relationships with humans, including mutualistic symbiosis and pathogenesis.

Question 24

Bacterial shape classification

Answer 24

spherical bacteria: cocci
Rod-shapes bacteria: bacilli
spiral-shaped bacteria: spirilli

Question 25

Bacterial metabolic process classification

Answer 25

Obligate aerobes - require oxygen for metabolism
Obligate anaerobes - cannot survive in oxygen-containing environments and can only carry out anaerobic metabolism
Facultative anaerobes - can survive in environments with or without oxygen and will toggle between metabolic processes based on the environment
Aerotolerant anaerobes - cannot use oxygen-containing, but can survive in an oxygen-containing environment.

Question 26

Envelope

Answer 26

cell wall and cell membrane of bacteria. Control the movement of solutes into and out of the cell.

Question 27

Gram-positive Bacteria

Answer 27

staining with crystal violet turns purple. Bacterial has thick cell wall composed of peptidoglycan and lipoteichoic acid.

Question 28

Gram-negative bacteria

Answer 28

staining with crystal violet turns pink-red. bacteria have a thin cell wall composed of peptidoglycan and an outer membrane containing phospholipids and lipopolysaccharides.

Question 29

Flagella

Answer 29

part of bacterial that allows it to be propelled towards food. Moving towards chemical response is called chemotaxis. Flagella contain filament composed of flagellin, a basal body that anchors and rotates the flagellum, and a hook that connects the two.

Question 30

Binary Fission

Answer 30

Prokaryotes. Chromosome replicates while the cell grows in size, until the cell wall begins to grow inward along the midline of the cell and divides it into two identical daughter cells.

Question 31

Plasmids

Answer 31

carry extrachromosomal material found in prokaryotes. plasmids may contain antibiotic resistance genes or virulence factors. Plasmids that can integrate into the genome are called episomes.

Question 32

Bacterial genetic recombination

Answer 32

Transformation - occurs when genetic material from the surroundings is taken up by a cell, which can incorporate this material into its genome.

Conjugation - the transfer of genetic material from one bacterium to another across a conjugation bridge. F+(has plasmid) copies and give F factor to F- to make it F+.

Transduction - transfer of genetic material from one bacterium to another via bacteriophage vector

Transposons - genetic elements that can insert into or remove themselves from the genome.

Question 33

Bacterial growth pattern

Answer 33

Lag phase - bacteria adapt to new local conditions
exponential(log) phase - growth then increases exponentially
stationary phase - resources are reduced, growth levels off
death phase - resources are depleted, bacterial die

Question 34

Viruses

Answer 34

genetic material protected by protein coat called capsid, and sometimes a lipid-containing envelope.
cannot survive and replicate without host cell. Individual virus particles called virions.

Question 35

Bacteriophages

Answer 35

viruses that target bacterial. Contain a tail sheath which injects genetic material into bacterium. Tail fibers allow bacteriophage to attach to host cell

Question 36

Viral genome

Answer 36

may be composed of DNA or RNA and may be single or double stranded.

Single-stranded RNA - may be positive sense(can be translated by host) or negative sense(requires a complementary strand to be synthesized by carried RNA replicase before translation)

Retrovirus - single-stranded RNA, from which complementary DNA strand is made using carried reverse transcriptase. DNA strand then integrated into genome

Question 37

Viral cycle

Answer 37

virus infects cell by attaching to specific receptors, and can then enter the cell by fusing with the plasma membrane, being brought in by endocytosis, or injecting their genome into the cell.

virus then reproduces by replicating and translating genetic material using the host cell’s ribosomes, tRNA, amino acids, and enzymes.

viral progeny released by cell death, lysis, or extrusion.

Question 38

bacteriophages two specific life cycles

Answer 38

Lytic cycle - bacteriophage produces massive number of new virions until the cell lyses. Bacteria in the lytic phase are termed virulent.

Lysogenic cycle - virus integrates into host genome as a provirus or prophage, which can then reproduce along with the cell. The provirus can remain in the genome indefinitely, or may leave the genome in response to a stimulus and enter the lytic cycle.

Question 39

Prions

Answer 39

infections proteins that trigger misfolding of other proteins, usually converting an a-helical structure to a B-pleated sheet. This decreases the solubility of the protein and increases its resistance to degradation

Question 40

viroids

Answer 40

plant pathogens that are small circles of complementary RNA that can trun off genes, resulting in metabolic and structural changes and, potentially, cell death.