Cells Flashcards
Plasma membrane
Regulates the movement of substances into and out of the cell. Has receptor molecules on it which allow it to respond to chemicals like hormones.
Cell wall
Supports plant cells. Mainly made of cellulose.
Nucleus
Controls the cell’s activities by controlling the transcription of DNA. DNA contains instructions to make proteins. The pores allow substances to move between the nucleus and the cytoplasm. Surrounded by a nuclear envelope.
Nucleolus
Makes ribosomes
Lysosome
Contains digestive enzymes which are kept separate from the cytoplasm by the lysosome’s surrounding membrane. The enzymes can be used to digest invading cells or break down worn components of the cell.
Ribosome
Where proteins are made. Either floats free or attached to RER. Made of proteins and RNA. Not surrounded by a membrane.
Rough endoplasmic reticulum (RER)
Folds and processes proteins that have been made at the ribosomes. A system of membranes enclosing a fluid filled space. Surface covered in ribosomes.
Smooth endoplasmic reticulum (SER)
Synthesises and processes lipids. A system of membranes enclosing a fluid filled space.
Vesicle
Transports substances in and out of the cell (via plasma membrane) and between organelles. Some formed at the Golgi apparatus or the endoplasmic reticulum, some formed at cell surface.
Golgi apparatus
Processes and packages new lipids and proteins. Also makes lysosomes.
Mitochondrion
Site of aerobic respiration, where ATP is produced.
Eukaryotic cell
cells with a nucleus and other membrane bound organelles
ultrastructure
the ultrastructure of a cell are the components which can be seen using an electron microscope
Nuclear envelope
Double membrane which protects nucleus from damage in the cytoplasm. Contains nuclear pores which allow molecules to move into and out of the nucleus.
Centrioles
Composed of microtubules. Two centrioles = centrosome. Involved in the assembly and organisation of spindle fibres during cell division
Prokaryotic cells do NOT have
ER Golgi Microtubules Nucleus & nuclear envelope Chromosomes Cilia Lysosomes
How do prokaryotic cells store DNA?
Prokaryotes only have one molecule of DNA (a chromosome) and this is CIRCULAR and NAKED (ie. no histone proteins)
Cell wall in Prokaryotes is made of
Peptidoglycan (aka murein)
The ribosomes in prokaryotes are
70S
What is the theory of endosymboisis?
that mitochondria and chloroplasts were formally free-living prokaryotic cells
flow chart of the organelles involved in protein production and trafficking
nucleus > ribosomes > rER > golgi apparatus > vesicles > plasma membrane
3 components of the cytoskeleton
Microfilaments
Intermediate filaments/fibres
Microtubules
Microfilament size
6-7 nm
Intermediate fibres size
10nm
Microtubule size
23nm
Protein in microfilament
actin
Protein in microtubule
tubulin
cytokinesis is…
the process in which the cytoplasm of a single eukaryotic cell divides to form 2 daughter cells
Function of microfilaments
- cell movement
- cell contraction during cytokinesis
- phagocytosis (moving phagocyte cells)
Function of microtubules
- determine shape of cell
- organelle movement (inc. vesicles)
- cilia/flagella
- centrioles for spindle fibres made from microtubules
Function of intermediate fibres
- give mechanical strength to cells
Microtubules allow vesicles to move between the golgi and the plasma membrane during
protein production and trafficking
Prokaryotic cell
cells with no membrane bound nucleus or organelles
examples of prokaryotic cells
bacteria eg. e.coli
examples of eukaryotic cells
single celled eg. yeast, amoebea
multicellular eg. humans, oak trees
transcription
the process of copying sections of DNA bas sequence to produce smaller molecules of mRNA
what happens after mRNA is made/ transcription has taken place?
mRNA is transported out of the nucleus via the nuclear pores and attaches to a ribosome (either free or attached to rER)
translation
the process by which the complimentary code carried by mRNA is decoded by tRNA into a sequence of amino acids (protein)
the front of the golgi is called
the ‘cis face’ or ‘forming face’
the back of the golgi is called
the ‘trans face’ or ‘maturing face’
How & when are proteins packaged into transport vesicles?
After being made in the ribosomes, protein moves through the cisternae and is packaged into transport vesicles
What happens to protein in the golgi apparatus?
proteins are structurally modified - carbohydrate ‘signals’ are added which bind to the receptor on target cells. This makes them complementary shapes
when proteins leave the golgi through vesicles they either leave as… or …
secretory vesicles or become lysosomes
exocytosis is
the transport of materials out of cells. Occurs when secretory vesicles containing modified protein fuses with the plasma membrane of a cell
which cytoskeleton component is responsible for organelle movement?
microtubules
which cytoskeleton component is responsible for cell movement?
microfilaments
which cytoskeleton component makes spindle fibres for pulling chromosomes apart?
microtubules
Name one cellular structure from the list below that is associated with the release of energy
mitochondria
Name one cellular structure from the list below that is associated with the movement of cilia
cytoskeleton
Name one cellular structure from the list below that is associated with the secretion of mucus
golgi (vesicle)
Describe the functions of glycoproteins in the cell surface membrane. (5)
1 (acting as) antigens;
2 identification / recognition, (of cells) as, self / non-self / AW;
ACCEPT foreign for non-self
3 cell signalling / described;
4 receptor / binding site, for, hormone / (chemical) signal / (medicinal /
named) drugs;
5 ref. to receptor / binding site / trigger, on transport proteins / AW;
6 cell adhesion / to hold cells together (in a tissue);
7 attach to water molecules (to stabilise membrane / cell);
Outline the sequence of events following the production of extracellular proteins that leads to their release from the cell. (3)
proteins moved to Golgi (apparatus / body);
processed / modified / AW;
e.g. carbohydrate group added
into vesicles;
(vesicle) moved to, plasma / cell surface, membrane;
(vesicles) fuse with membrane;
exocytosis;
