Biology Chapter 1: The Cell (4 Stars) Flashcards
The cell theory has 4 basic tenets:
All living things = cells.
cell = 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.
Viruses are not considered living things because they are acellular, _______ without the assistance of a host cell, and may contain RNA as their genetic material.
cannot reproduce
Eukaryotes have _______ organelles, a nucleus, and may form multicellular organisms.
membrane-bound
The cell membrane and membranes of organelles contain ________, which organize to form hydrophilic interior and exterior surfaces with a hydrophobic core.
phospholipids
The _______ suspends the organelles and allows diffusion of molecules throughout the cell.
cytosol
The ______ 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 ______ and cytosol. DNA is organized into coding regions called genes.
nucleus
The ______ is a subsection of the nucleus in which ribosomal RNA (rRNA) is synthesized.
nucleolus
Mitochondria contain an outer and inner membrane. The _____membrane forms a barrier with the cytosol; the ______ membrane is folded into cristae and contains enzymes for the electron transport chain. Between the membranes is the intermembrane space; inside the inner mitochondrial membrane is the __________.
inner membrane.
outer membrane
mitochondrial matrix.
_______ contain hydrolytic enzymes that can break down substances ingested by endocytosis and cellular waste products. When these enzymes are released, autolysis of the cell can occur.
Lysosomes
The endoplasmic reticulum (ER) is a series of interconnected membranes and is continuous with the _________. The rough ER (RER) is studded with ribosomes, which permit ________ of proteins destined for secretion. The smooth ER (SER) is used for lipid synthesis and detoxification.
nuclear envelope.
translation
The Golgi apparatus consists of stacked membrane-bound sacs in which cellular products can be _______, packaged, and directed to specific cellular locations.
modified
________ contain hydrogen peroxide and can break down very long chain fatty acids via β-oxidation. They also participate in phospholipid synthesis and the pentose phosphate pathway.
Peroxisomes
The _______ provides stability and rigidity to the overall structure of the cell, while also providing transport pathways for molecules within the cell.
cytoskeleton
________ are composed of actin. They 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.
Microfilaments
Microtubules are composed of tubulin. They create pathways for motor proteins like _____ and ______ to carry vesicles.
kinesin and dynein
________ filaments are involved in cell–cell adhesion or maintenance of the integrity of the cytoskeleton; they help anchor organelles. Common examples include _______ and ______.
Intermediate
keratin and desmin.
________ tissues cover the body and line its cavities, protecting against pathogen invasion and desiccation. Some epithelial cells absorb or secrete substances, or participate in sensation.
Epithelial
In most organs, epithelial cells form the _______, or the functional parts of the organ.
parenchyma
Epithelial cells may be _______, with one side facing a lumen or the outside world, and the other side facing blood vessels and structural cells.
polarized
Epithelia can be classified by the number of layers they contain: _______ epithelia have one layer, stratified epithelia have many layers, and _________ epithelia appear to have multiple layers because of differences in cell heights, but actually have only one layer.
simple epithelia
pseudostratified epithelia
Epithelia can be classified by the shapes of the cells they contain: cuboidal cells are cube-shaped, columnar cells are long and _______, and squamous cells are ____ and scalelike.
columnar cells are narrow
squamous cells are flat
Connective tissues support the body and provide a framework for ______ cells.
epithelial cells.
In most organs, connective tissues form the stroma or support structure by secreting materials to form an ________ matrix.
extracellular matrix.
Bone, cartilage, tendons, ligaments, adipose tissue, and _____ are all connective tissues.
blood
Prokaryotes do not contain membrane-bound organelles; they organize their genetic material in a single _______ molecule of DNA concentrated in the nucleoid region.
circular
_____ are often extremophiles, living in harsh environments (high temperature, high salinity, no light) and often using alternative sources of energy, like chemosynthesis. They have similarities to both eukaryotes (start translation with methionine, similar RNA polymerases, histones) and bacteria (single circular chromosome, divide by binary fission or budding).
Archaea
______ is the only non-prokaryotic domain.
Eukarya
Spherical bacteria are called ______
cocci.
Rod-shaped bacteria are called _______
bacilli.
Spiral-shaped bacteria are called _____
spirilli.
______ aerobes require oxygen for metabolism.
Obligate
Obligate ________ cannot survive in oxygen-containing environments and can only carry out anaerobic metabolism.
anaerobes
_________ can survive in environments with or without oxygen and will toggle metabolic processes based on the environment.
Facultative anaerobes
_________ cannot use oxygen for metabolism, but can survive in an oxygen-containing environment.
Aerotolerant anaerobes
The cell wall and cell membrane of bacteria form the _______. Together, they control the movement of solutes into and out of the cell.
envelope
Bacteria can be classified by the color their cell walls turn during Gram staining with a crystal violet stain, followed by a counterstain with safranin.
Gram-positive bacteria turn ________,
purple
Gram-_______ bacteria have a thick cell wall composed of peptidoglycan and lipoteichoic acid.
positive (purple)
Gram-negative bacteria have a _____ cell wall composed of peptidoglycan and an outer membrane containing phospholipids and lipopolysaccharides.
thin (pink)
Bacteria may have one, two, or many flagella that generate propulsion to move the bacterium toward food or away from immune cells. Moving in response to chemical stimuli is called________. Bacterial flagella contain a filament composed of flagellin, a basal body that anchors and rotates the flagellum, and a ______ that connects the two.
chemotaxis.
hook
Prokaryotes carry out the electron transport chain using the ____ membrane.
cell
Prokaryotic ribosomes are _______ than eukaryotic ribosomes
smaller
(30S and 50S, rather than 40S and 60S).
Prokaryotes multiply through _______, in which the 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.
binary fission
In addition to the single circular chromosome in prokaryotes, extrachromosomal material can be carried in _______.
plasmids.
Plasmids may contain antibiotic resistance genes or virulence factors.
________ is the acquisition of genetic material from the environment, which can be integrated into the bacterial genome.
Transformation
_________ is the transfer of genetic material from one bacterium to another across a ______ bridge; a plasmid can be transferred from F+ cells to F– cells, or a portion of the genome can be transferred from an Hfr cell to a recipient.
Conjugation
________ is the transfer of genetic material from one bacterium to another using a bacteriophage as a vector.
Transduction
_________ are genetic elements that can insert into or remove themselves from the genome.
Transposons
The bacteria adapt to new local conditions during the ______ phase.
lag
Growth then increases exponentially during the _______ phase.
exponential (log) phase.
As resources are reduced, growth levels off during the ______ phase.
stationary phase.
As resources become insufficient, bacteria undergo a ______ phase.
death
Viruses contain genetic material, a ________, and sometimes a lipid-containing envelope.
a protein coat (capsid)
Viruses are ______ intracellular parasites, meaning that they cannot survive and replicate outside of a host cell. Individual virus particles are called virions.
obligate
Bacteriophages are viruses that target _______. In addition to the other structures, they contain a tail sheath, which injects the genetic material into a bacterium, and _______, which allow the bacteriophage to attach to the host cell.
bacteria.
tail fibers
_______ may be composed of DNA or RNA and may be single- or doublestranded.
Viruses
Single-stranded RNA viruses may be __________ (can be translated by the host cell) or _________ (a complementary strand must be synthesized using RNA replicase, which can then be translated).
positive sense
negative sense
Retroviruses contain a single-stranded _____ genome, to which a complementary DNA strand is made using reverse transcriptase.
RNA
DNA strand can then be integrated into the genome.
Viruses infect cells by attaching to specific receptors, and then either fusing with the plasma membrane, being brought in by _______, or injecting their genome into the cell.
endocytosis
The virus reproduces by replicating and translating genetic material using the host cell’s ribosomes, _____, amino acids, and enzymes.
tRNA,
Viral _______ are released through cell death, lysis, or extrusion.
progeny
In the lytic cycle, the bacteriophage produces massive numbers of new _____ until the cell lyses.
virions
In the _______, the virus integrates into the host genome as a provirus or prophage, which can then reproduce along with the cell.
lysogenic cycle,
The provirus then leaves the genome in response to a stimulus at some later time and enters the lytic cycle.
_____ are infectious proteins that trigger misfolding of other proteins, usually converting an α-helical structure to a β-pleated sheet. This decreases the solubility and degradability of the misfolded protein.
Prions
_____ are plant pathogens that are small circles of complementary RNA that can turn off genes, resulting in metabolic and structural derangements of the cell and—potentially—cell death
Viroids
DNA is organized into coding regions called _____.
DNA is organized into coding regions called genes.
Mitochondria can divide independently of the nucleus via ________; they can trigger apoptosis by releasing mitochondrial enzymes into the cytoplasm.
binary fission
Microtubules contribute to the structure of cilia and flagella, where they are organized into # ____ pairs of microtubules in a ring with two microtubules at the center. Centrioles are found in centrosomes and are involved in microtubule organization in the mitotic spindle.
nine pairs (9 + 2 structure)
_________ are found in centrosomes and are involved in microtubule organization in the mitotic spindle.
Centrioles
gram-negative bacteria turn ________.
pink
Plasmids that can integrate into the genome are called _______
episomes.
Individual virus particles are called _______
virions.
Bacteria in the _____ phase are termed virulent.
lytic
Mitochondria is also know as ______ of the cell
Powerhouse
Identify the bacteria present in the testtube.
Facultative Aerobes
Obligate Anaerobes
Acrotocrant anaerobes
Obligate Aerobes
Microacrophilcs
Oxygen would be expected to be present at the top of the tube and absent at the bottom. Therefore, obligate aerobes (#1 in Figure 15) would only be found at the top, and obligate anaerobes (#2) only at the bottom. Facultative aerobes (#3) would be found throughout the tube, but with a greater distribution at the top due to the increased efficiency of aerobic metabolism. So-called microacrophilcs (#4) arc a group of microorganisms that require oxygen for metabolism but arc poisoned by high concentrations. Acrotolcrant anaerobes (#5) would be spread evenly throughout the tube.
Idenitify the missing cell components
