Ch. 4 cell structure Flashcards
Define Prokarya
Before nucleus
Define Eukarya
“True” nucleus
When were cells discovered?
In 1665 by Robert Hook
What is Cell Theory? (hint there’s 3 answers)
1) All organisms are composed of cells
2) cells are the smallest living thing
3) cells arise from pre-existing cells
What’s a resolution?
The minimum distance that 2 points can be apart and still be distinguished as 2 separate points
What are the 4 types of microscopes?
1) light - use magnifying lens and visible light
2) electron - use beams of electrons
3) transmission electron - transmit electrons through materials
4) scanning electron - beam electrons onto surface of specimen
What are the 4 basic structure similarities of all cells? In other words, what do all cells have?
1) DNA
2) Ribosomes
3) cytoplasm
4) plasma membrane
What is Cytosol?
Liquid component of cytoplasm
What do prokaryotes (archaea and bacteria) lack?
A nucleus
What did Robert Hook call cells?
Cellulae
What did Matthias Schleiden discover in 1838?
That cells make up the tissue of plants
What did Anton van Leeuwenhoek call cells?
animalcules
What did Theodor Schwann discover in 1839? What did it lead to?
Cells make up animal tissues which led to cell theory being born
What’s Cell Theory?
The explanation for the observation that all organisms are composed of cells
What’s the Modern form of Cell Theory? (there are 3 parts)
1) all organisms have 1+ cell in which metabolism and heredity occur w/in these cells
2) Cells are the smallest living thing and the basic unit of organization of all organisms
3) Cells arise from division of pre-existing cells
What’s the surface area-to-volume ratio?
As a cell’s size increases, its volume increases more rapidly than its surface area
What’s a compound microscope?
One that magnifies in stages using multiple lenses and resolve structures more than 200 nm apart
What does Immunohistochemistry use?
Antibodies to bond to specific proteins after being chemically bonded
What are prokaryotes?
simplest organism that primarily has a single circular molecule of DNA found in the nucleoid
What are eukaryotes?
Have DNA organized into linear chromosomes segregated into a nucleus
What’s the difference between a prokaryote and a eukaryote?
Pro: has nucleotide
Euk: has a nucleus
What’s cytoplasm?
Semifluid matrix that fills the interior of the cell
What’s a ribosome?
large macromolecular machines made of RNA and protein that synthesizes all cellular proteins
What’s the plasma membrane?
an enclosure of a cell that separates its contents from its surroundings
What’s a plasmodesmata (in plants)?
Where plants are connected in the cell walls
What’re flagella?
a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility
What’s a gap junction?
intercellular connections between a multitude of animal cell-types. They directly connect the cytoplasm of two cells, which allows various molecules, ions and electrical impulses to directly pass through a regulated gate between cells
What’re tight junctions?
Leak-proof seals that surrounds an epithelial cell
What’s an Adherens junction?
cell-cell adhesion complexes that are continuously assembled and disassembled, allowing cells within a tissue to respond to forces, biochemical signals and structural changes in their microenvironment
What is a Bacterial Microcompartment (BCM)?
something that isolates a specific metabolic process or stores a particular substance
Define Cell Walls
Walls that protect the cell, maintain its shape, and prevent excess uptake/loss of water
What are bacteria flagella?
protein rings embedded in the plasma membrane and a cell wall w/ long protein fibers extending from this
What’s archaellum?
a structure that appears related to a different bacterial external structure known as a pilus and formed by a disk of membrane proteins w/ a protein filament extending from the cell
What’s the endromembrane system?
a system that weaves through the cell interior and has numerous organelles that are used to compartmentalize multiple biochemical processes
What’s the central vacuole?
a large membrane-bounded sac that stores proteins, pigments, and waste materials in plant cells
Whta’s a visicle?
small sacs that store and transport a variety of materials
What’s a nucleus?
Found in the center of a cell, it has genetic info that enables the synthesis of nearly all proteins
What’s a nucleous?
a region where intensive synthesis of the ribosomal RNA takes place
What’s a nuclear envelope?
surface of the nucleus which is bounded by 2 phospholipid bilayered membranes
What are nuclear pores?
Small holes on the surface of the nuclear envelope that allow ions and small molecules to diffuse freely between the nucleoplasm and cytoplasm while controlling the passage of proteins and RNA-protein complexes
What’s a nuclear lamina?
the inner surface of the nuclear envelope; gives nucleus its shape
What’s a chromatin?
a complex structure in which DNA is divided into multiple linear chromosomes and organized with proteins
What is rough endoplasmic reticulum (RER)?
attachment of ribosomes to the membrane and gives a rough appearance; synthesis of proteins is secreted
What’s smooth endoplasmic reticulum (SER)?
relatively few bounded ribosomes that have a variety of function; makes membranes
What’s the endoplasmic reticulum (ER)?
the largest internal membrane in eukaryotic cells
What does a Golgi apparatus do?
collects, packages and distributes molecules synthesized at one location and used at another w/in the cell or outside of it
What’s the receiving end of a Golgi apparatus called? Where’s it located?
Cis face; located near ER
What’s the exit end of the Golgi apparatus called?
Trans face
How do proteins transport through the end-membrane system? (hint, there’s 4 parts)
1) proteins synthesized by ribosomes on RER; transported to ER
2) diffused through cell and fused w/ cis face
3) modified, packaged into vesicles for transport
4) travel in vesicles to either the plasma membrane to go outside or to other locations in the cell via the trans face
What are lipid droplets?
organelles w/ different structures from the rest of the end-membrane system and consist of a neutral lipid core surrounded by a layer of phospholipid
What are micro bodies?
things that contain enzymes in the cells that help eukaryotic cells organize their metabolism
What’s a peroxisome contain?
enzymes that oxidize fatty acids
What’s a tonoplast?
channels for water outside vacuoles that help the cell maintain its tonicity
What’s a grana?
closed compartments of stacked membranes in chloroplasts
What’s a thylakoid?
light-capturing photosynthesis pigment in grana
What’s a amyloplast?
a leucoplast that stores the starch, amylose
What’s a leucoplast?
a DNA-containing organelle that lacks pigment and complex internal structure; could serve as a starch storage area
How is a plastid produced?
division of existing placids; are chloroplasts, leucoplasts and amyloplasts
What’s the Theory of Endosymbiosis?
Some of todays eukaryotic organelles evolved by a symbiosis (relationship) between 2 free living cells in which a prokaryote (was one cell) got engulfed and became a new cell (eukaryote) ; examples being the mitochondria and chloroplasts
What does the mitochondria do?
metabolizes sugar to produce ATP
What do chloroplasts do?
harness light energy to produce ATP and synthesize sugars
What’s an actin filament (microfilament)?
long fibers composed of 2 protein chains loosely twined together w/ subunits of globular proteins called actin
What’s a microtubule?
largest part of cytoskeletal elements; consist of a ring of 13 protein proto-filaments w/ alpha and beta tubulin subunits
Are positive if away from nuclear center and negative if close
What’s an intermediate filament?
most durable element and once formed, are stable and cannot breakdown; have various functions depending on their type
Where are centrioles found?
in the cells of animal and plant cells; a cylindrical organelle composed mainly of a protein called tubulin
What are the 4 components to move material through the microtubules?
1) a vesicle or organelle that needs to be transported
2) a motor protein
3) a connector molecule that connects the vesicle to the motor
4) microtubules that the vesicle will ride on (like a train on a rail)
What’s myosin?
a protein that helps w/ muscle contraction
What’s a primary wall?
laid down walls when a plant cell is still growing
What’s the middle lamella?
what glues cells together between the walls of adjacent cells to a sticky substance
What’s a secondary wall?
deposited inside a primary wall of fully expanded cells
What’s an integrin?
part of the plasma membrane that extends into cytoplasm and attaches microfilaments and intermediate filaments of the cytoskeleton
What’s a glycolipid?
cell surface markers
What’s a major histocompatibility complex (MHC)?
genes that help the immune system distinguish “self” cells from “nonself” cells
What’re Hemidesmosomes?
focal adhesions that connect cells to the basal lamina or other ECM
What’re separate junctions?
found in invertebrates and vertebras and form a barrier that can seal off a sheet of cells
What’s communicating junctions?
small areas that allow communication between cells through small
