Biology Cellular Flashcards
The cell is the fundamental unit of all living ___
things
Every function in biology involves a process that occurs within ___ or at the interface between cells
cells
All living things are ___ of cells
composed
The cell is the basic ___ unit of life
functional
The chemical reactions of life take place inside the ___
cell
___ arise only from pre-existing cells
cells
Cells carry genetic information in the form of ___. This genetic material is passed from parent cell to daughter ___
DNA, cell
There are millions of species of “living things” that can be divided into ___ kingdoms
six
Bacteria, Archaea, ___, Fungi, Plantae, and Animalia
Protista
Within these six kingdoms are two major types of cells: ___ and eukaryotic
prokaryotic
The word prokaryote means “before nucleus,” which alludes to the structure of these organisms as a whole: they do not contain ___ or membrane-bound organelles
nuclei
While eukaryotes possess all the cellular structures mentioned in this chapter, ___ only possess a cell membrane, cytoplasm
prokaryotes
According to the generally accepted fluid mosaic model, the cell membrane consists of a ___ bilayer with proteins embedded throughout
phospholipid
The ___ and many of the proteins can move freely within the membrane
lipids
Phospholipid molecules are arranged such that the long, nonpolar, hydrophobic, “fatty” chains of carbon and hydrogen face each other, with the phosphorus-containing, polar, hydrophilic heads facing ___
outward
As a result of its lipid bilayer structure, a plasma membrane is readily permeable to other small, nonpolar, hydrophobic molecules such as oxygen, and small ___ molecules, such as water
polar
Enclosed by the nuclear membrane, the ___ contains DNA wound around structural proteins called histones
nucleus
During DNA replication, DNA tightly winds around the ___, compacting (loose DNA) into chromosomes
histones
During transcription, however, DNA unwinds itself from the ___ allowing for transcription to occur
histones
In addition, the nucleus contains a dense structure called the ___ where ribosomal RNA (rRNA) synthesis occurs
nucleolus
Prokaryotes do not have ___ and therefore do not possess histones to organize their DNA into linear chromosomes
nuclei
Instead, prokaryotic ___ is organized into small circular chromosomes located in a region of the cell termed the nucleoid
DNA
Ribosomes facilitate protein production and are made of __ rRNA sequences, called ribosomal subunits
two
Although rRNA molecules are synthesized in the nucleolus of eukaryotes, they function either in the ___ as unbound ribosomes or on the outer membrane of the rough endoplasmic reticulum as bound ribosomes
cytoplasm
The endoplasmic reticulum (ER) is a network of membrane-enclosed spaces involved in the transport of materials throughout the ___, particularly those materials destined to be secreted by the cell
cell
Rough ER contains ___ (which gives it a “rough” appearance under microscopy) and plays an important role in the production of proteins
ribosomes
Smooth ER does not contain ribosomes and so is not involved with protein ___ but is instead involved with metabolism and the production of libpids
synthesis
The Golgi apparatus is the primary site for cellular ___
trafficking
The Golgi apparatus receives vesicles and their contents from the smooth ER and then modifies them (i.e. glycosylation), repackages them into ___, and distributes them to the cell surface for exocytosis
vesicles
Mitochondria are the sites of aerobic respiration within the ___; they are responsible for the conversion of sugars, fats, and other sources of fuel into usable energy, specifically adenosine triphosphate (ATP)
cell
The outer membrane forms a barrier with the cytosol; the inner membrane is folded into ___ and contains enzymes for the electron transport chain
cristae
___ also contain their own genome
Mitochondria
Located within the matrix, this DNA (genome) is independent of the cell genome and resembles circular bacterial ___
chromosomes
The presence of an independent ___ allows mitochondria to divide independently of the nucleus via binary fission
genome
Most of the cell’s metabolic activity occurs in the cytoplasm which includes the ___ (the cellular fluid contained within the cell membrane and all the organelles of the cell
cytosol
Transport within the cytoplasm occurs by ___ (streaming movement within the cell
cyclosis
Vacuoles are larger than vesicles and are more likely to be found in plant than in ___ cells
animal
Centrioles are composed of microtubules and are involved in ___ organization during cell division
spindle
___ are not bound by a membrane
centrioles
Animal cells usually have a pair of centrioles oriented at ___ angles to each other that lie in a region of the cell called the centrosome
right
Plant cells do not contain ___
centrioles
___ are membrane-bound vesicles that contain ___ involved in intracellular digestion
hydrolytic enzymes
An injured or dying cell may self-destruct by rupturing the lysosome membrane and releasing its hydrolytic enzymes; this process is called ___
autolysis
The cytoskeleton is composed of microtubules, microfilaments and intermediate ___
filaments
Microtubules are hollow rods made up of polymerized ___ that radiate throughout the cell and provide it with support
tubulin
Centrioles, which direct the separation of chromosomes during cell division, are composed of ___
microtubules
Microfilaments are solid rods of ___, which are important in cell movement as well as support
actin
Muscle contraction, for example, is based on the interaction of actin with ___
myosin
Intermediate filaments serve as the structural backbone of the cell, as they are able to withstand a tremendous amount of ___
tension
Along with making the cell structure more rigid, ___ help anchor organelles to their respective places in the cell
intermediate filaments
___ is a passive process that requires no external source of energy
simple diffusion
___ is the simple diffusion of water from a region of lower solute concentration to a region of higher solute concentration
osmosis
When the cytoplasm has a ___ solute concentration than the extracellular medium, the medium is said to be hypertonic to the cell, and water will flow out of the cell into the surrounding medium
lower
When the cytoplasm of a cell has a lower solute concentration that the extracellular medium, the cell can ___
shrivel
When the cell shrivels, this is called ___
plasmolysis
During osmosis, water moves toward ___ equilibrium
isotonic
In other words, water always moves in the direction that will make both solutions ___ to one another
isotonic
If the extracellular environment is less concentrated than the cytoplasm of the cell, the extracellular medium is said to be ___
hypotonic
In a hypotonic solution, water will flow ___ the cell, causing it to swell an lyse (burst)
into
Red blood cells will burst if placed in ___ water
distilled
Facilitated diffusion (passive transport) is the net movement of dissolved particles ___ their concentration gradient through special channels or carrier proteins in the cell membrane. This process, like simple diffusion, does not require energy
down
Active transport is the net movement of dissolved particles ___ their concentration gradients with the help of transport proteins
against
Unlike diffusion, ___ transport requires energy
active
___ move two or more ions or molecules in the same direction
symporters
___ exchange one or more ions (or molecules) for another ion or molecule across the membrane
antiporters
___ are energy-dependent carriers (require ATP); e.g., sodium-potassium pump
pumps
___ is a process in which the cell membrane invaginates, forming a vesicle that contains extracellular medium
endocytosis
___ is the ingestion of fluids or small particles
pinocytosis
___ is the engulfing of large particles
phagocytosis
In both endocytosis and exocytosis, material never actually ___ through the cell membrane
passes
___ is a period of growth and chromosome replication
interphase
Mitosis begins with ___, which prepares the cell for karyokinesis (nuclear division)
prophase
First part of prophase, ___ is condensed into clearly defined chromosomes.
chromatin
Second part of prophase, the nuclear membrane dissolves which is necessary for nuclear ___
division
Final part of prophase, the ___ pairs separate and move towards opposite poles of the cell
centriole
During prophase, the centrioles will serve as anchoring points to pull and separate the ___
chromosomes
In metaphase, the ___ are now at opposite poles of the cell and anchor themselves to the cell membrane through the formation of spindle fibers
centrioles
During metaphase, additional spindle fibers radiate outwards from the centriole towards the chromosomes and attach to each chromatid at the ___, a protein located on the centromere of the chromosome
kinetochore
In metaphase, the spindle fiber aligns the chromosomes along the ___ plate
metaphase
Anaphase is marked by the separation of sister ___of each chromosome
chromatids
First part of Anaphase, the centromeres split so that each chromatid has its own distinct ___, thus allowing their separation
centromere
During Anaphase, the sister chromatids are pulled toward the opposite poles of the cell by the shortening of the spindle ___
fibers
During telophase, the ___ apparatus disappears
spindle
During telophase, a nuclear ___ forms around each set of newly formed chromosomes
nuclear
During telophase, each nucleus contains the same number of chromosomes (the ___ number, 2N) as the original or parent nucleus
diploid
During telophase the chromosomes ___, resuming their interphase form
uncoil
During cytokinesis, near the end of telophase, the cytoplasm divides into two daughter cells, each with a complete nucleus and its own set of ___
organelles
During cytokinesis in ___ cells, a cleavage furrow forms, and the cell membrane indents along the equator of the cell, eventually pinching through the cell and separating the two nuclei
animal
During cytokinesis in plant cells, a cell plate forms between the two ___, effectively splitting the plant cell in half and allowing the cell to divide
nuclei
Sexual reproduction occurs via the fusion of two ___ - specialized sex cells produced by each parent
gametes
For sexual reproduction to occur, Meiosis, the process by which sex cells are produced, must ___
occur
Meiosis is similar to mitosis in that a cell duplicates its ___ before undergoing the process
chromosomes
Mitosis preserves the diploid number of the cell, meiosis produces ___ (1N) cells, halving the number of chromosomes
haploid
The haploid nature of sex cells important, as it ensures that upon fertilization (sex cell fusion) the resulting cell is ___
diploid
___ (i.e. haploid, diploid) refers to how many chromosomes an organism has in a homologous set
ploidy
___ sets are chromosomes that share structure and gene locations, but can have different alleles
homologous
humans are ___, possessing two chromosomes in a homologous pair that will have a gene for hair color at the same location
diploid
However, one chromosome may contain an ___ for brown hair while the other has the allele for blonde hair
allele
As in mitosis, the interphase of meiosis is characterized by a diploid parent cell going through S phase, thereby replicating its __
DNA
In interphase the change is that each chromosome now has ___ sister chromatids
two
In interphase, each homologous pair has a total of ___ sister chromatids
four
During the first meiotic division, after replication of the parent cell genome, ___ occurs
meiosis
During meiosis, the first meiotic division yields two haploid (1N) daughter ___
cells
during meiosis, the first meiotic division separates the pair of homologous chromosomes, not ___
chromatids
Prophase I of meiosis shares similarities to prophase of mitosis: the chromatin condenses into chromosomes, the spindle apparatus forms, and the ___ and nuclear membrane disappear
nucleoli
The major difference in prophase I of meiosis is the occurrence of ___ over
crossing
___ is the genetic exchange between chromatids of homologous chromosomes and is vital for a species, as it increases genetic diversity
crossing over
First part of crossing over involves homologous chromosomes coming together and intertwining in a process called ___
synapsis
After the first part of crossing over, where homologous chromosomes intertwine, the resulting structure is often called a ___, as there is a total of four sister chromatids involved
tetrad
___: During meiosis, the exact parts of the chromosomes where sister chromatids interact
chiasmata
Once synapsis begins, chromatids of homologous chromosomes break at corresponding points and exchange equivalent pieces of ___
DNA
Crossing over does not occur between sister chromatids on the same ___, as these chromatids are identical and would not produce any genetic variation
chromosomes
___: homologous pairs (tetrads) align at the equatorial plane and each pair attaches to a separate spindle fiber at the kinetochore
metaphase I
In anaphase I: The homologous pairs separate and are pulled to ___ poles of the cell
opposite
During anaphase I when homologous pairs separate and are pulled to opposite poles of the cell, this is called ___
disjunction
During anaphase I (disjunction), each chromosome of paternal origin separates (or disjoins) from its ___ of maternal origin, and either chromosome can end up in either daughter cell
homologue
During anaphase I (disjunction), the distribution of homologous chromosomes to the two intermediate daughter cells is random with respect to parental ___
origin
Nondisjunction occurs when cells do not separate appropriately during ___
meiosis
A nuclear membrane forms around each new nucleus during ___ thereby forming two haploid cells (1N) in which each chromosome has two sister chromatids
telophase I
during ___ one, two haploid cells are often called intermediate daughter cells
telophase I
Meiosis II shares many similarities with mitosis, specifically that in both of these processes sister chromatids are ___
separated
One major difference between meiosis II and mitosis is the fact that in meiosis II both the parent (intermediate daughter cells) and daughter cells are haploid, while in mitosis all cells remain ___
diploid
During prophase II, the ___ envelope dissolves, nucleoli disappear, the centrioles migrate to opposite poles, and the spindle apparatus begins to form
nuclear
During metaphase II, the ___ line up on the metaphase plate
chromosomes
During anaphase II, the sister chromatids of the chromosomes are separated and are pulled apart by shortening ___ fibers
spindle
during anaphase II each separated sister chromatid is now considered a ___ itself
chromosome
during telophase II, a nuclear membrane forms around each new set of ___
chomosomes
Cytokinesis follows ___ and two haploid daughter cells are formed per intermediate daughter cell
telophase II
By completion of meiosis II, up to four ___ daughter cells are produced per gametocyte (parent cell of meiosis II)
haploid
Telophase II results in up (italicized) to four haploid daughter cells because in oogenesis, female gametogenesis, two or three of the potential gametes become polar bodies and are ___ by the body
absorbed
