bio paper 1 Flashcards
what type of microscope do you use to examine biological specimens?
light microscope
what are enzymes?
proteins that function as biological catalysts.
what is the location called where smaller molecules fit into on an enzyme?
active site.
what is the lock and key hypothesis?
the shape of the active site matches the shape of its substrate.
there are 3 stages of how an enzyme splits a substrate. what is stage 1?
stage 1, the substrate collides with active site of the enzyme and becomes attached.
there are 3 stages of how an enzyme splits a substrate. what is stage 2?
stage 2, the enzyme catalyses’ breakdown of substrate.
there are 3 stages of how an enzyme splits a substrate. what is stage 3?
stage 3, enzyme molecule is unchanged and the product is released from active site.
what can affect enzymes rate of reaction?
pH or temperature.
what does it mean by the term ‘denatured enzyme’?
the substrate no longer fits the active site as pH or temp has effected the shape of the enzyme.
what is the formula for rate of reaction?
rate of reaction = amount of substrate used or amount of product formed/ time taken
why does the rate of reaction drop if the temperature is too high?
because the enzymes have denatured
what is the optimum pH for the small intestines and the stomach enzymes?
small intestines : pH 7.5
stomach : pH2
interphase
- cell grows and increases the amount of subcellular structures.
duplicated DNA.
prophase
- mitosis begins.
chromosomes condense.
nucleus membrane brakes down.
chromosomes live free in the cytoplasm.
metaphase
- chromosomes line up at the center of the cell.
anaphase
- cell fibers pull apart the chromosomes to opposite ends of the cell.
What is cell DEFERENTIATION?
The process by in which a cell becomes a specialised cell for its job.
This makes multicellular organisms work more efficiently.
What is a catalyst?
molecules that speed up a chemical reactions without being changed by the reaction.
What is the order for the cell cycle?
Interphase, prophase, metaphase, anaphase, telophase/cytokinesis
What does sexual reproduction produce?
Genetically different cells.
How many chromosome does the human cell contain?
Diploid number: 46
Haploid number: 23
In sexual reproduction, the father and the mother produce gametes. What are they commonly known as in animals?
Sperm and egg cells
What happens during fertilisation?
The male gamete fuses with the female gamete forming a Zygote.
Zygotes are diploid cells. What does this mean?
They have full sets of chromosomes. (46)
What type of reproduction is mitosis?
Asexual reproduction
Why is mitosis used?
To grow and replace cells that have been damaged.
What is cell elongation?
Where a plant cell expands, making the cell bigger and so making the plant grow.
What is cancer?
Uncontrollable cell division.
What is a tumor and why can it caused cancer?
A tumor is a mass of abnormal cells. This can turn into cancer if the tumor Invades and destroys surrounding tissue.