Biology Chapter 1: The Cell Flashcards
What are the four parts of the cell theory?
- All living things are composed of cells.
- The cell is the basic functional unit of life.
- Cells arise only from preexisting cells.
- Cells carry genetic information in the form of DNA. This genetic material is passed on from parent to daughter cell.
Why are viruses not considered living things?
- Acellular
- Cannot reproduce without the assistance of a host cell, and may contain RNA as their genetic material
What is the nucleolus?
a subsection of the nucleus in which ribosomal RNA is synthesized
What does the release of mitochondrial enzymes into the cytoplasm do?
triggers apoptosis
What is the rough ER used for?
Has ribosomes on it, so used for translation of proteins
What is the smooth ER used for?
lipid synthesis and detoxification
What is the golgi apparatus?
It is membrane bound sacs in which cellular products can be modified, packaged, and directed to specific cellular locations
What are peroxisomes?
Contain hydrogen peroxide and can break down very long chain fatty acids via beta-oxidation. They also parrticipate in phospholipid synthesis and the pentose phosphate pathway.
What are microfilliments composed of? What do they do?
Actin - They provide structural protection for the cell. and can cause contraction through interactions with myosin, also help create the cleavage furrow during cytokinesis in mitosis.
What are microtubules composed of? What do they do?
They are composed of tubulin. they create pathways for motor proteins, such as kinesin and dynein. They also contribute to the structure of cilia and flagella.
How are cilia and flagella organized?
Into 9 pairs of microtubules in a ring with two in the center.
Where are centrioles found? How are they used?
In centrosomes and are involved in microtubule organization in the mitotic spindle.
What are intermediate filaments used for?
cell-cell adhesion or maintenance of the integrity of the cytoskeleton; they help anchor organelles. Common examples include keratin and desmin.
What are epithelial tissues?
Cover the body and line cavities
What are the parenchyma?
Functional parts of the organ, usually made up of epithelial cells.
Are epithelial cells charged?
Sometimes they may be polarized, one side facing a lumen and the other side facing blood vessels and structural cells.
What is the difference between simple, stratified and psuedostratified epithelia?
Simple = 1 layer Stratified = Multiple layers Psuedostratified = appear to have multiple layers because of difference in cell heights, but actually only have one layer.
What are the three types of epithelia classifications?
cubioidal (cube-shaped), columnar (long and narrow), squamous (flat and scale-like)
What is the stroma?
Support structure
What are connective tissues?
Bone, cartilage, tendons, ligaments, adipose tissue, blood
What are the three domains of life?
archaea, bacteria, eukarya
What are the three classes of bacteria?
Cocci (spherical)
Bacilli (rod-shaped)
Spirilli (spiral)
What are obligate aerobes?
Require oxygen for metabolism
What are obligate anaerobes?
cannot survive in oxygen-containing environments and can only carry out anerobic metabolism
What are facultative anaerobes?
Can survive in environments with or without oxygen and will toggle metabolic processes based on the environment
What are aerotolerant anaerobes?
Cannot use oxygen for metabolism, but can survive in an oxygen-containing environment.
What is the cell wall/membrane of a bacteria cell called?
envelope
What is gram-staining?
Way to classify bacteria. If gram-positive, then they turn purple, if gram-negative, then they turn pink-red
What are the characteristics of gram-positive?
have a thick cell wall composed of peptidoglycan and lipoteichoic acid
What are the characteristics of gram-negative?
Have a thin cell wall composed of peptidoglycan and an outer membrane containing phospholipids and lipopolysaccharides.
What is chemotaxis?
It is moving in response to chemical stimuli
How do prokaryotes call out the electron transport chain?
The cell membrane
What are the ribosome subunits for eukaryotes vs. prokaryotes?
pro = 30S and 50S euk = 40S and 60S
What are plasmids?
Another way prokaryotes can carry extrachromosomal material. they may contain antibiotic resistance or virulence factors.
What are plasmids that integrate into the genome called?
episomes
What is transformation?
Acquisition of genetic material from the environment, which can be integrated into the bacterial genome
What is conjugation?
transfer of genetic material from one bacterium to another across a conjugation bridge
What is transduction?
Transfer of genetic material from one bacterium to another using a bacteriophage as a vector.
What are transposons?
Genetic elements that can insert into or remove themselves from the genome.
What are the 4 phases of bacterial growth?
Lag phase: adapt to new local conditions
Exponential (log) phase: growth increases exponentially
Stationary phase: resources are reduced and growth levels off
Death phase: resources become insufficient
What do viruses contain?
genetic material, protein coat, and sometimes a lipid-containing envelope.
What are bacteriophages?
They are viruses that target bacteria, contain a tail sheath (injects) and tail fibers (holds on).
What are positive sense and negative sense RNA?
positive sense can be translated by the host cell. negative sense must be read by a RNA replicase to make a complementary strand.
What are retroviruses?
They contain a single-stranded RNA genome, to which a complementary DNA strand is make using reverse transcriptase.
What are three ways that viruses can infect cells?
- Attach to different receptors
- fuse to plasma membrane
- brought in by endocytosis OR
- injecting their genome
What are the two life cycles of bacteriophages?
Lytic cycle - produces massive numbers of new virons until cell lyses
Lysogenic cyle - integrates into the host genome & then reproduces along with the cell
What are prions?
infectious proteins that trigger misfolding of other proteins, usually converting an alpha helical structure to a beta-pleated sheet
Viroids?
They are plant pathogens that are small circles of complementary RNA that can turn off genes.
