Biology Flashcards
What is the eye made up of?
-Retina
-Sclera
-Lens
-Iris
-Pupil
-Optic nerve
-Cornea
-Ciliary Muscles
-Suspensory Ligaments
-Fovea
What is the Retina layer made up of? (HINT: Cell types)
Rod cells - Light Intensity Reception
Cone Cells - Red, Green, Blue colour reception
How do we work out Total Magnification?
Magnification = Eyepiece x Objective
How do we find actual size?
Actual size = Image / magnification
What is a genome?
The entire genetic code in an organism
What is DNA?
A double helix polymer - stores genetic code
What is a gene?
Portion of DNA that codes for a protein (mapping these allows us to identify causes of disorders).
What is genotype?
An organisms specific genetic code
What is phenotype?
How the genotype is expressed in physical characteristics.
What are bases made from?
A sugar/phosphate group.
What are the bases? Which go complimentary to each other?
Guanine - G goes with Cytosine - C
Thymine - T goes with Adenine - A
What is a Eukaryotic Cell?
A cell with a nucleus. Their DNA is found here. For e.g An animal cell or plant cell
What is a Prokaryotic Cell?
A cell without a nucleus. Their DNA can be found in Plasmids (loop of DNA) or Chromosomal DNA
What is a feature of the cell membrane?
Semi permeable - allowing certain substances to pass through into the cell - controls what leaves and enters a cell.
What is the cell wall made of?
Cellulose.
What are Enzymes?
Enzymes are special proteins that act as biological catalysts, often breaking down molecules into smaller ones (eg polymers into monomers)
What is amylase and what does is it responsible for?
It is an enzyme (biological catalyst) that breaks down starch into glucose.
What is lipase and what is it responsible for?
An enzyme (biological catalyst) that breaks down lipids (fats) into glycerol and fatty acids.
What is protease and what does it break down?
Protease is an enzyme (biological catalyst) that breaks down proteins into amino acids.
How many bases are needed to code for an amino acid?
3 bases are needed
What is (for eg) BB or bb known as?
Homozygous alleles.
What is (for eg) Bb known as?
Heterozygous alleles
What is the order of the reflex ark?
Stimulus
Receptors (in sense organs)
Sensory Neurone
Relay Neurone
Motor Neurone
Effector (muscle or gland to carry out a quick involuntary response)
What is in the CNS?
Brain
Spinal Cord
Nerves
Explain Adult Stem cells
Found in the body eg bone morrow.
It is multipotent - there is a limit to what they can become usually the type of tissue surrounding them.
Explain Embryonic Stem Cells
Found in the inner cell mass of an embryo
It is pluripotent - Can differentiate into any kind of cell
Explain Meristem Cells.
Stem cells found in the Meristems of plants e.g shoots and roots
Able to produce any kind of specialised cell throughout the life of the plant.
What are stem cells?
Cells that haven’t been differentiated yet and can go on to become a number of different types of cells.
What is the role of the dendron?
Carries the electrical impulse
What is the role of the dendrite?
Receives impulses from receptor cells.
What is the role of the axon?
To carry the electrical impulse
What are the role of axon terminals?
Pass impulses to other neurones
What is the role of the myelin sheath?
The fatty layer surrounding neurones that insulate them to stop energy loss.
What is a synapse?
Gaps inbetween neurones. When an impulse reaches a synapse, neurotransmitter substance is released across through axon terminals. It gets detected on the other side by dendrites which generates a new impulse.
What are the stages of growth in plants?
Stage 1 - Mitosis
Stage 2 - Elongation
Stage 3 - Differentiation
What is a Dipliod cell?
23 pairs (46 single) of chromosomes
What is a haploid cell?
Half a set of chromosomes (23 single chromosomes) Half genetic information (gametes)
Where is DNA found?
In the nucleus in long strands called chromosomes, formed by 2 strands that twist to form a double helix shape.
What are the 4 base pairs and which goes with which?
Adenine - A
Cytosine - C
Guanine - G
Thymine - T
G goes with C
A goes with T
What is the bonding between each of these bases?
Hydrogen bonds.
Adenine and Thymine have two bonds
Guanine and Cytosine have 3 bonds
What are each of the bases connected to?
A sugar with each sugar connected to a phosphate.
What is genotype?
The alleles that an organism has
What is phenotype
What the organism looks like.
What happens during Transcription?
First stage of Protein Synthesis
Takes place in the nucleus. The RNA polymerase attaches to the non-coding section of DNA
The enzyme separates the two stands of DNA
RNA polymerase continues to move along the DNA to reach the coding region of a gene
RNA Polymerase adds complementary RNA nucleotides to the template strand.
RNA polymerase links the RNA nucleotides together to form a strand of mRNA
What happens during translation?
The strand of mRNA travels out the nucleus through a nuclear pore
In the cryptoplasm, a ribosome attaches to the mRNA strand.
A tRNA molecule pairs up with each codon (3 bases)
The ribosome joins together the amino acids carried by the tRNA molecules.
This results in the formation of a polypeptide
The types and order of amino acids in the chain cause it to fold into a specific shape
What replaces Thymine in the m/tRNA?
Uracil - U
So DNA - ATA in m/tRNA (depending) would complementary base pair that as UAU
What causes mutation
A change in the bases of a gene creating a genetic variant.
What are the blood groups?
A
B
AB
O
What are mendels laws?
Each gamete receives only onr factor for a characteristic
The version of a factor a gamete receives is random and does not depend on the other factors in the gamete
Some versions of a factor are more powerful than others and always have an effect in the offspring
