cell biology and interactions Flashcards
(37 cards)
what does the plasma membrane do
controls traffic between cell and external environment via the use of transmembrane proteins
what kind of molecules cannot diffuse freely though the plasma membrane
polar, organic molecules, ions and proteins
what do channel proteins do
form a selective ‘pore’ through a membrane that permits specific molecules to pass through
what do carrier proteins do
‘capture’ molecules on one side of a membrane, then change shape to allow the molecules to pass through
name a few differences between plant and animal cells
- plant cells have a cell wall and chloroplasts, whereas animal cells do not
- plant cells have large vacuoles whereas animals cells may have several small vacuoles
- animal cells have centrioles always present, whereas only lower plant form plant cells have them
- plant cells contain glyoxysomes and amyloplasts whereas animal cells do not
describe the nuclear envelope
a porous double membrane separating the nucleus from the cytoplasm
describe nuclear pores
small holes in the nuclear envelope that facilitate and regulate the exchange of materials such as proteins and RNA, between nucleus and cytoplasm
what is the name of the proteins that aid folding of DNA in a chromosome to tightly pack it
histones
what are the two classes of chromatin
heterochromatin - tightly condensed and generally inactive in transcription
euchromatin - less condensed and contains actively transcribed genes
what is the nucleolus involved in
the production and assembly of ribosomes
what is the cytoskeleton
the cellular scaffolding contained within the cytoplasm in all cells
what are the three types of filaments found in eukaryotic cytoskeletons
microfilaments = involved in muscle contraction
intermediate filaments - keratin
microtubules = involved in cell division
where are microfilaments most concentrated
just beneath the cell membrane
what are microfilaments composed of and what are their functions
made of two intertwined actin chains (made from the monomer unit; globular actin)
they resist tension (water), maintain cellular shape, signal transduction, perform muscular contraction and used in cytokinesis
are microfilaments more stable than intermediate filaments
no
name 4 functions of intermediate filaments
- They function in the maintenance of cell shape by bearing tension
- Organise the internal 3D structure of the cell
- Anchor organelles
- Participate in some cell-to-cell junctions
what are microtubules made of
alpha and beta tubulin
describe the structure of microtubules
the tubulin bundles in hollow cylindrical filaments that are then arranged in an imperfect helix
name the 4 functions of microtubules
- transportation of organelles
- form the cytoskeleton of cilia and flagella #
- play a key role in the synthesis of the cell wall in plants
- form the mitotic spindle
what are centrioles made of
microtubules
what is ATP synthase
an enzyme that creates ATP from ADP and Pi, using energy
what does the nucleolus contain
the DNA that controls the synthesis of ribosomal RNA
how many subunits does a nuclear envelope/ pore have
4
what’s the tissue that surrounds the heart called
the pericardial membrane
