Chapter 6: A Tour of the Cell Flashcards
is the simplest collection of matter that can be alive
cells
Senses & Responds to environment
Exchanges materials and energy w/ surroundings
Microscopic command centers
takes cells apart andseparates the major organelles from one another
Cell fractionation
enables scientists to determine the functions of organelles
cell fractionation
Basic features of all cells:
Plasma membrane
Semifluid substance called cytosol
Chromosomes (carry genes)
Ribosomes (make proteins)
Semifluid substance
cytosol
is a selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell
plasma membrane
A eukaryotic cell has internal membranes that divide the cell into compartments—
organelles
The basic fabric of biological membranes is what
a double layer of phospholipids and other lipids
an internal membrane bound sac or compartment that serves one or more specialized functions inside eukaryotic cells.
organelle
use the information from the DNA to make proteins1
ribosomes
contains most of the cell’s genes and is usually the most conspicuous organelle
nucleus
encloses the nucleus, separating it from the cytoplasm
nuclear envelope
In the nucleus, DNA is organized into discrete units called
chromosomes
In its uncondensed state, each chromosome contains one DNA molecule associated with proteins (histones) and is referred to as
chromatin
condenses to form discrete chromosomes as a cell prepares to divide
chromatin
is located within the nucleus and is the site of ribosomal RNA (rRNA) synthesis
nucleolus
are complexes of two subunits made of ribosomal RNA and protein
ribosomes
carry out protein synthesis
ribosomes
in what two locations does ribosomes caary out protein synthesis
cytosol
nuclear envelope
regulates protein traffic and performs metabolic functions in the cell
endomembrane system
what does the endomembrane system consist of
Nuclear envelope
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Plasma membrane
These components of the endomembrane system are either continuous or connected via transfer by
vesicles
accounts for more than half of the total membrane in many eukaryotic cells
endoplasmic reticulum (ER
the two regions of the ER
Rough ER
Smooth ER
whose surface is studded with ribosomes
Rough ER
which lacks ribosomes
Smooth ER
proteins covalently bonded to carbohydrates
Glycoproteins
is produced in rough ER of pancreatic cells and then secreted into blood stream
Insulin
consists of flattened membranous sacs called cisternae
Golgi apparatus
Modifies products of the ER
Golgi apparatus
flattened membranous sacs
cisternae
Manufactures certain macromolecules
Golgi apparatus
Sorts and packages materials into transport vesicles
Golgi apparatus
is a membranous sac of hydrolytic enzymes that can digest macromolecules
Lysosome
are made by rough ER and then transferred to the Golgi apparatus for further processing
Hydrolytic enzymes and lysosomal membranes
Some types of cells can engulf another cell by
phagocytosis
this forms a food vacuole
phagocytosis
fuses with the food vacuole and digests the molecules
lysosome
also use enzymes to recycle thecell’s own organelles and macromolecules,a process called autophagy
lysosomes
using enzymes to recycle thecell’s own organelles and macromolecules
autophagy
are specialized metabolic compartments bounded by a single membrane
Peroxisomes
They breakdown fatty acids and amino acids and produce hydrogen peroxide as a byproduct
Peroxisomes
are large vesicles derived from the ER and Golgi apparatus
vacuoles
perform a variety of functions in different kinds of cells
vacuoles
are formed by phagocytosi
food vacuoles
found in many freshwater protists, pump excess water out of cells
contractile vacuoles
found in many mature plant cells, hold organic compounds and water
central vacuoles
an organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur.
mitochondria
smooth outer membrane and an inner membrane folded into what
cristae
The inner membrane creates two compartments: called what
intermembrane space and mitochondrial matrix
Some metabolic steps of cellular respiration are catalyzed in the what
mitochondrial matrix
green pigment
chlorophyll
contain the green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesis
chloroplasts
membranous sacs
thylakoids
thylakoids are stacked to form what
granum
the internal fluid
stroma
The chloroplast is one of a group of plant organelles, called
plastids
states that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a large anaerobic bacteria (prokaryote).
endosymbiont theory
is a network of fibers extending throughout the cytoplasm
cytoskeleton
It organizes the cell’s structures and activities, anchoring many organelles
cytoskeleton
what three types of molecular structures does the cytoskeleton compose?
microtubules
Intermediate filaments
Microfilaments
helps to support the cell and maintain its shape
cytoskeleton
the cytoskeleton interacts with what to produce cell motility
motor proteins
are the thickest of the three components of the cytoskeleton
microtubules
are the thinnest components
microfilaments
are fibers with diameters in a middle range
Intermediate filaments
are hollow rods about 25 nm in diameter and about 200 nm to 25 microns long
microtubules
Microtubules are constructed of dimers of
tubulin
what are the functions of microtubules
Shape of cell
Guiding movement of organelles
Separating chromosomes during cell division
In animal cells, microtubules grow out from a what near the nucleus
centrosome
In animal cells, the centrosome has a pair of what each with nine triplets of microtubules arranged in a ring
centrioles
control the beating of flagella and cilia,
microtubules
microtubule-containing extensions thatproject from some cells
cilia and flagella
Many unicellular eukaryotes are propelled through water by
cilia
flagella
what is the motion of flagella
direction of swimming
what is the motion of cilia
direction of organism’s movement
that anchors the cilium or flagellum
basal body
which drives the bending movements of a cilium or flagellum
dynein
A motor protein called
dynein
has two “feet” that “walk” along microtubules
dynein
what cause the microtubules to bend, rather than slide, because the microtubules are held in place
Movements of the feet
are solid rods built as actin subunits
Microfilaments
microfilaments form a what just inside the plasma membrane to help support the cell’s shape
cortex
Bundles of microfilaments make up the core of what
microvilli
Microfilaments that function in cellular motility contain the protein what
myosin
cellular extensions
pseudopodia
is a circular flow of cytoplasm within cells, driven by actin-myosin interactions
cytoplasmic streaming
is a circular flow of cytoplasm within cells, driven by actin-myosin interactions
cytoplasmic streaming
range in diameter from 8 to 12 nanometers, larger than microfilamentsbut smaller than microtubules
intermediate filaments
Animal cells lack cell walls but are covered by an elaborate
extracellular matrix (ECM)
The ECM is made up of glycoproteins such as what
collagen, proteoglycans, and fibronectin
ECM proteins bind to receptor proteins in the plasma membrane called
integrins
Neighboring cells in tissues, organs, or organ systems often adhere, interact, and communicate through direct physical contact due to what
cell junction
are channels that perforate plant cell walls
Plasmodesmata
cell junction in plants
Plasmodesmata
water and small solutes (and sometimes proteins and RNA) can pass from cell to cell
plasmodesmata
membranes of neighboring cells are pressed together, preve
tight junctions
(anchoring junctions) fasten cells together into strong sheets
desmosomes
(communicating junctions) provide cytoplasmic channels between adjacent cells
gap junctions
