Semester 2 Exam Revision Flashcards
Science
Define ‘allele’
Different versions of a gene
Define ‘dominant’
An allele that is displayed.
Define ‘recessive’
An allele that is masked by a dominant trait, unless you receive two.
Define ‘heterozygous’
When a person possesses two different alleles.
Define ‘homozygous’
When a person possesses two of the same alleles.
Define ‘genotype’
The alleles inherited for a gene.
Define ‘phenotype’
Observable traits as a result of the genotype.
Where is DNA found and why is it important?
Cell Nucleus - carries the genetic information that controls cell growth and development
Define ‘haploid’
Cell containing one set of chromosomes
Define ‘diploid’
Cell containing two sets of chromosomes
Define ‘gamete’
Sex cells - sperm or ova
Define ‘gonad’
An organ that produces and releases eggs or sperm
Define ‘karyotype’
The general appearance of a complete set of chromosomes in the cells of a species
What can we tell from a karyotype?
Genetic abnormalities in chromosome structure
Describe the process of Mitosis
- Occurs in all body/somatic cells
-Stages of Prophase, metaphase, anaphase, telophase - The cells produced are identical to the parent cell
- Produces 2 cells that have 46 chromosomes
- 1 round of cell division
What is the purpose of mitosis?
- The purpose is for the growth, repair and replacement of cells
Describe the process of meiosis
- Occurs in the gonads (sex organs)
- The cells produced are not genetically identical to the parent cell
- 2 rounds of division
- Daughter cells have 23 chromosomes
What is the purpose of meiosis?
The purpose is to produce sex cells for sexual reproduction
Define ‘variation’
The differences between individuals of the same species due to genetic and environmental factors.
Define ‘species’
An organism’s ability to successfully reproduce fertile offspring
Define ‘adaptation’
Genetic variation that increases chances of survival in an environment
Define ‘evolution’
The change in the characteristics of a species over generations.
Define ‘selective pressure’
An environmental factor that favours a particular trait.
Define ‘artificial selection’
The identification of desired traits in animals/ plants.
Define ‘speciation’
The formation of new species
Describe the natural selection process
- Genetic variation in a population due to a selective pressure or mutation.
- Survivors have a greater chance of mating and passing on inherited traits to their offspring.
- Species with the favourable gene will survive and those without will be hunted.
- Offspring are better suited & will become greater in the population.
Define ‘homologous structures’
They have different functions, but the same basic structure.
The similarity in anatomy results from recent common ancestry.
Define ‘big bang theory’
A theory that all matter and energy in the universe began expanding in all directions 10 to 15 billion years ago.
Define ‘red shift’
Light moving towards an observer shows a longer wavelength and lower frequency
Define ‘blue shift’
Light moving towards from an observer shows a shorter wavelength and high frequency
Define ‘Doppler effect’
An observed change in the frequency of a wave when the source or observer is moving.
Referring to the evolutionary sequence of stars diagram - What is stage A?
Protostar forms
Referring to the evolutionary sequence of stars diagram - What is stage B?
Star forms and begins to shine.
Referring to the evolutionary sequence of stars diagram - What is stage C?
Red supergiant forms from stars heavier than our sun.
Referring to the evolutionary sequence of stars diagram - What is stage D?
Red giant star forms from a main sequence star.
Referring to the evolutionary sequence of stars diagram - What is stage E?
Large nebula forms as gravity pulls dust and gases together.
Referring to the evolutionary sequence of stars diagram - What is stage F?
White dwarf forms at the core of a giant red star.
Referring to the evolutionary sequence of stars diagram - What is stage G?
Supernova formed from a red super giant.
Referring to the evolutionary sequence of stars diagram - What is stage H?
Small planetary nebula formed after a supernova event.
Referring to the evolutionary sequence of stars diagram - What is stage I?
Black hole forms from a red super giant explosion (supernova).
Referring to the evolutionary sequence of stars diagram - What is stage J?
Pulsar (neutron star) forms.
Provide evidence to support the big bang theory
- Red Shift of Galaxies
- Cosmic Microwave Background Radiation
- Abundance of Light Elements (H, He and Li)
The diagram below is of the Doppler effect. With reference to frequency, wavelength and pitch, explain how it provides evidence of an expanding universe.
When objects are closer to Earth, they have blue shift, as they have a higher frequency, shorter wavelength and high pitch.
When objects are further from Earth, they have red shift, as they have a lower frequency, longer wavelength and low pitch.
Therefore, objects moving to red shift with a lower frequency, longer wavelength and low pitch show evidence that the Universe is expanding.
Define ‘energy’
The capacity to do work
What is energy measured in?
Joules - J
Define ‘mechanical energy’
Energy possessed by an object due its motion or position
Define ‘kinetic energy’
Energy an object has due to its motion
Define ‘mechanical potential energy’
Energy an object has due to its position
Define ‘gravitational potential energy’
Energy that is stored in an object because of its vertical position
Define ‘elastic potential energy’
Energy stored in a spring or other elastic object
State the Law of Conservation of Energy
Energy cannot be created nor destroyed only rearranged
Provide examples of potential energy
Chemical, gravitational, elastic and nuclear
Provide examples of kinetic energy
Sound, thermal and electromagnetic.
Define ‘chromatin’
Unwound DNA found in the nucleus
Define ‘chromatid’
Each of two thread-like strands into which a chromosome divides during mitosis
Variation in Offspring
- Crossing Over
- Random Assortment
Define ‘crossing over’
The exchange of genetic information between homologous chromosomes
Define ‘random assortment’
The random organisation of chromosomes in the middle of the cell during the first stage of meiosis.
What is the theory of evolution?
Every living thing on the planet originated from a common ancestor
What was Lamarck’s theory of evolution?
The organism’s offspring inherited traits that the parent adapted or acquired over time.
What was a common example of Lamarck’s theory?
- The stretching of a giraffe’s neck as it fed on high-up leaves from trees.
- The stretching of the neck from the parent would lead to the children having longer and stretchier necks.
What was Charles Darwin’s evolution theory?
- Natural Selection
- A species will adapt over generations to best suit their environments based on selection
Define ‘genetic variation’
Mutations within genes that are passed on through generations
Define ‘environmental variation’
Acquired characteristics which are selected in response to the environment
Define ‘mutations’
Random alterations in genes produce new gene options and new phenotype outcomes
Define ‘gene pool’
Consists of all the copies of all the genes in that population
Define ‘allele frequency’
How common an allele is in a population
Define ‘gene flow’
Immigration/emigration - can increase/decrease the diversity in the local population by introducing new alleles or removing them.
Types of Adaptation
- Structural: Change to the body
- Behavioural: Change to behaviour
- Physiological: Change to body function
What are ‘Density Dependent Factors’?
P - Predators
A - Availability of resources
N - Nutrient supply
D - Disease/Pathogenic spread
A - Accumulation of Wastes
What are ‘Density Independent Factors’?
P - Phenomena (natural disaster)
A - Abiotic Factors (temperatures)
W - Weather Conditions (flood)
Types of Speciation
- Convergent: Unrelated species in similar ecosystems have similar traits that are favourable
- Divergent: A population gets split into two due to geographic barriers
- Co-evolution: Unrelated species that evolve alongside each other.
Comparative Anatomy
- Homologous: Organs with similar structures but not similar functions
- Analogous: Similarities in species which aren’t closely related but live in similar environments
- Vestigial: A structure that has been reduced in size or has lost its function.
Comparative Embryology
Embryos of different vertebrae species have homologous structures
Biogeography:
The study of the distribution of species and ecosystems in geographic space and through geographic time.
What does Hubble’s Law state?
The further away a galaxy is, the greater the red shift, and so the faster it’s moving away from us.
Define ‘carbon sequestration’
The long-term storage of carbon in plants, soils, geologic formations, and the ocean.
Does mass or velocity have a greater impact on the kinetic energy of an object?
Velocity significantly influences an object’s kinetic energy, as kinetic energy is directly proportional to mass but exponentially proportional to velocity.
Doubling mass doubles kinetic energy, but doubling velocity quadruples kinetic energy.
