Molecules
a DNA molecule wrapped around a core of eight histone proteins
Why are red blood cells atypical cells?
no nucleus
State a similarity between chloroplasts and mitochondria
-size
- double membrane
- contains DNA
- inner membranes increase surface area
-...
conduction type in myelinated fibers
saltatory
Name 2 phytohormones involved in growth
auxin
cytokinin
gibberellin
the region around a star in which life is possible
What is the Goldilocks zone?
State the phases of the cell cycle in the correct order.
G1, S and G2 as the stages of interphase, followed by mitosis and then cytokinesis
This molecule facilitates a certain form of endocytosis
What is clathrin
How is peristalsis in the digestive system controlled?
involuntary control by the enteric nervous system (ENS).
Name the hormone controlling fruit ripening
ethylene/ethene
having both hydrophilic and hydrophobic properties
What is amphipathic?
An experiment providing evidence for the origin of carbon compounds
What is the Miller-Urey experiment.
An advantage of eukaryotes over prokaryotes because of the presence of a nucleus
What is post-transcriptional modification.
Outline what happens when a pain receptor is stimulated
Entry of positively charged ions causes the threshold potential to be reached and nerve impulses then pass through the neurons to the brain, where pain is perceived
Name 2 adaptations of phloem sieve tubes for translocation
sieve plates,
reduced cytoplasm and organelles,
no nucleus for sieve tube elements
plasmodesmata between sieve tubes and companion cells
State all the bonds/interactions that can be formed in the tertiary structure of a protein
hydrogen bonds, ionic bonds, disulfide covalent bonds and hydrophobic interactions
Outline the 2 reasons which can lead to uncontrolled cell division.
mutations in proto-oncogenes that convert them to oncogenes and mutations in tumour suppressor genes
State the number of plasma membranes that an oxygen molecule passes when it diffuses from the air of an alveolus into a red blood cell
State all the cells involved in a reflex arc
sensory neuron
(interneuron)
motor neuron
effector
Name the tissues of a leaf from top to bottom.
(cuticle)
upper epidermis
palisade mesophyll
spongy mesophyll
lower epidermis
State all the covalent bonds found in:
- amylose
- glycogen
- cellulose
amylose: alpha 1,4
glycogen: alpha 1,4 and alpha 1,6
cellulose: beta 1,4
State the full name and function of CAMs
“cell-adhesion molecules” (CAMs) different forms of CAM are used for different types of cell–cell junction
Name all the organelles and processes in the correct order involved in the production of a sodium channel until it is functional in the correct location.
Nucleus - transcription
RER & ribosome - translation
Golgi apparatur - modification
vesicle
exocytosis - integration into the membrane
Baroreceptors monitor blood pressure. Chemoreceptors monitor blood pH and concentrations of oxygen and carbon dioxide.
stomata have been counted in 5 fields of view giving the following values:
5-6-3-5-6
What is the stomatal density, knowing that the diameter of the field of view is 500 um?
average: 5
area: 12,56 mm^2
density = 5/12,56 = 0,39 /mm^2