Exam semster 1 Flashcards
Shape of a DNA molecule
Double Helix or spiral ladder
Trisomy
Three copies of a chromosome instead of the normal pair of two e.g. Down syndrome is the result of an extra chromosome 21
Monosomy
A condition in which there is only one copy of a particular chromosome in a cell e.g. Turner’s syndrome results in only one sex chromosome (xo)
Prophase
The process separates the duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells.
Metaphase
-Chromosomes line up along the equator (middle) of the cell
-Microtubule spindle fibres attach to the centromere of each chromosome
Anaphase
Sister chromatids are separated and move to opposite poles
Telephase
Two nuclei form, each with a diploid number of chromosomes
Meiosis
-Meiosis is a special process of nuclear division that results in the production of sperm or ova (gametes or sex cells)
-Each daughter cell contains half the original number of chromosomes, the haploid number (23)
Mitosis
Used to produce new cells for repair, growth and regeneration
Stages of Mitosis
-Interphase
-Prophase
-Metaphase
-Anaphase
-Telephase
-Cytokinesis
(These stages happen twice in Meiosis)
Dominant trait
Refers to a trait (phenotype) that requires only one allele to be present for its expression in a heterozygote. Denoted by a capital letter.
Recessive trait
Refers to a trait (phenotype) that will only be expressed in the absence of the allele for the dominant trait. Denoted by a lower case letter.
Carrier
Refers to someone who is heterozygous for a particular trait and carries the allele for the recessive trait (such as the alleles for blue eyes or red hair)
Process of a Fraternal twins
Fraternal twins develop in the very early stages of the division following fertilisation, where clusters of a few cells develop into two separate individuals.
Process of Identical twins
Identical twins result as each cluster has the same genetic makeup as the other.
Pedigree gender rule
-A square is always used to represent a male
-A circle is always used to represent a female
Features of Metals
-Solid at room temperature, except for mercury which is a liquid
-Can be polished to produce a high shine
-Good conductors of electricity and heat
-Usually melt at high temperatures
Non-metal elements
-At room temperature, 11 are gasses, 10 are solids, 1 is liquid
Features of solid non-metals
-Cannot be polished to give a shine like metals; they are usually dull or glassy.
-They are brittle, which means they shatter when they are hit
-Cannot be bent into shape
-They are usually poor conductors of electricity and heat
-They usually melt at low temperatures
Characteristics of patterns down a group
-Atomic number and mass number: Increases
-Atomic radius: Increases
-Melting points: Decreases for groups 1 to 5 and increases for group 15 to 18
-Reactivity: Metals become more reactive and non-metals become less reactive
-Metallic character: Increases
Characteristics of patterns across a period
-Atomic number and mass number: Increases
-Atomic radius: Decreases
-Melting points: Generally increase then decreases
-Reactivity: Is high, then decreases and then increases. Group 18 elements are inert and do not react
-Metallic character: Decreases
Distance-time graphs
-A distance-time graph shows how far an object travels as time
-The slope or gradient of a distance-time graph is equivalent to the objects average speed over time interval
Displacement-time graph
-In a displacement-time graph, the slope or gradient of the line is equal to the velocity of the object
-The steeper the line (and the greater the gradient) the faster the object is moving
Speed-time graphs
-The area below a speed-time graph is the distance the object has travelled up to a given point
