Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
74 Cards in this Set
- Front
- Back
|
How does a DNA molecule get replicated?
|
1. 'Unzips' itself
2. New bases move in and bind to form the same base pairs as the mother DNA molecule. |
|
|
How many different types of cells are there in the human body?
|
Over 300
|
|
|
What are some examples of proteins?
|
Keratin, protease, amylase, actin, collagen, lipase
|
|
|
What do genes carry the instructions for?
|
Inherited characteristics
|
|
|
What gives cells different characteristics?
|
The different proteins that they produce
|
|
|
What are the three main causes of a mutation?
|
1. Mistakes in copying DNA
2. Ionising radiation 3. Heavy metal ions |
|
|
What are many inherited diseases caused by?
|
Incorrect proteins being produced as a result of a mutation.
|
|
|
What is the backbone made of in DNA?
|
Alternating sugar and phosphate molecules forming a chain.
|
|
|
Which bases are purines?
Which bases are pyrimidines? |
A and G
C and T |
|
|
How do biologists know the pairing of bases?
|
Purines bound together would form too wide a bond if pyrimidines were also bound together. Therefore purines must bind to pyrimidines only and vice versa.
|
|
|
A can only bond to T. G can only bond to C. Why is this?
|
A and T form 2 hydrogen bonds. G and C form 3 hydrogen bonds. If A bonded with G, only 1 hydrogen bond would form which would be too weak to hold the double helix together.
|
|
|
What is an amino acid chain also known as (other than protein)?
|
A polypeptide
|
|
|
What are the 6 functional roles of proteins?
|
RST 2xCI
Regulatory - insulin Structural - keratin Transport - haemoglobin Catalytic - protease Contractile- actin Immunological - gammaglobulin |
|
|
What are the 4 phases of each of M1 and M2?
|
1. Prophase
2. Metaphase 3. Anaphase 4. Telophase and cytokinesis |
|
|
What happens during interphase?
|
The chromosomes are replicated - DNA replication
|
|
|
What happens during prophase?
|
1. The nuclear envelope is fragmented and centrosomes assemble at each end of the cell
2. Synapsis where non-sister chromatids line up against each other gene by gene 3. Some genetic information is swapped between the chromatids. |
|
|
What happens during metaphase?
|
1. Centrosomes move to opposite ends of the cell
2. The spindles stretch and attach to middle of chromosomes |
|
|
What happens during anaphase?
|
Homologuous chromosomes are pulled apart by the centrosomes
|
|
|
What happens during telophase and cytokinesis?
|
Each end of the cell has haploid chromosomes which are sister chromatids with some non-sister elements.
During cytokinesis the cytoplasm splits. |
|
|
What are the transcription and translation processes used for?
|
Protein synthesis
|
|
|
What is transcription?
|
The process of copying DNA into mRNA
|
|
|
What is translation?
|
The process of translating mRNA into proteins.
|
|
|
What are the physical differences between RNA and DNA?
|
- The sugar molecules in the backbone are different.
- Uracil is used instead of Thymine - It is only single helixed. |
|
|
What are the three steps of transcription?
|
1. Initiation
2. Elongation 3. Termination |
|
|
What happens during initiation?
|
RNA Polymerase pries the double helix apart into single helixes.
It binds to a promoter (the start site of transcription). The RNA Polymerase begins making the RNA strand. |
|
|
What happens during elongation?
|
The polymerase moves along the DNA strands and the DNA strand is rewinded behind the polymerase.
|
|
|
What happens during termination?
|
The termination codon is reached and the RNA polymerase stops elongating the RNA.
The RNA is cut free and leaves the nucleus to ribosomes. |
|
|
What happens between transcription and translation to make the RNA strand mRNA.
|
Enzymes 'cap' and 'tail' the RNA strand.
RNA splicing occurs where introns (non-coding bases) are removed and exons are reconnected. |
|
|
What happens during translation?
|
1. mRNA is assembled in the ribosome.
2. Codons on the mRNA code for certain amino acids. Amino acids are floating freely in the cytoplasm. 3. tRNA forms containing anticodons which then collect the needed amino acids. 4. The amino acids form a polypeptide chain along the back of the mRNA. |
|
|
How is DNA cloning achieved?
|
Using a bacteria plasmid.
|
|
|
What is the basic process of DNA cloning?
|
1. The gene of interest is inserted into the plasmid.
2. The plasmid is put back into the bacterial cell. 3. The bacterial cell is grown to form bacteria containing the cloned gene. 4. The protein created by the new bacteria can be harvested and used in humans (e.g insulin) |
|
|
What is the group of phosphate, sugar and base called in DNA?
|
A nucleotide
|
|
|
Which gamete determines the sex of a child?
|
The sperm because ova can only contain X while sperm can contain Y or X (Y has dominant alleles)
|
|
|
What are three differences between RNA and DNA?
|
1. RNA has ribose sugar rather than deoxyribose
2. RNA uses Uracil rather than Thymine 3. RNA is a single strand rather than dual strand DNA |
|
|
Now for human evolution...
|
...
|
|
|
When were the first hominids around (after what period)?
|
After the miocine period, 6-7 million years ago
|
|
|
What is the oldest hominid found?
|
Sahelanthropus genus
|
|
|
What is the general evolutionary order of hominids from oldest to newest?
|
Sahelanthropus -> Australopithecus -> Paranthropus -> Homo
|
|
|
When were Australopithecus around?
|
Between 4 and 2.5 million years ago.
|
|
|
What is an obvious development between Sahelanthropus and Australopithecus?
|
Australopithecus was bipedal.
|
|
|
What did bipedal characteristics help ancient hominids with?
|
Seeing predators over long grass, and brain and body cooling
|
|
|
What size was the Australopithecus brain case? Why was it?
|
Around 430 cc because of body proportion - The males were only 1.3m tall.
|
|
|
Which species/genera had flat, broad noses and which didn't? Why is this?
|
Australopithecus, Paranthropus, Homo erectus and Homo habilis. A broad nose was needed to prevent loss of moisture to a hot climate through breathing.
|
|
|
What is gradualism in relation to Neanderthals -> Homo sapiens?
|
Evidence for direct evolution from neanderthalensis to sapiens. Fossils used for this evidence are only in Australasian area.
|
|
|
What is punctual evolution in relation to Neanderthals -> Sapiens?
|
Evidence to show that Neanderthals are separate species from humans but this evidence is in European areas.
|
|
|
What is the replacement model compared to the regional continuity model?
|
The replacement model shows that hominids migrated to other continents but died out there and returned later. The regional continuity model shows that hominids migrated back and forth throughout the ages.
|
|
|
What is evolution?
|
The gradual change in organisms over time.
|
|
|
How many living species are there?
|
Between 3 and 20 million.
|
|
|
What percentage of species that have ever lived is still living?
|
99%
|
|
|
What are physical traits that assist in survival called?
|
Fitness
|
|
|
What does this arise from?
|
Adaptations
|
|
|
What do adaptations result from?
|
Natural selection
|
|
|
What is paleontology?
|
The identification and interpretation of fossils that provide a direct evidence of previous life on Earth.
|
|
|
What are fossils and what is needed for them to occur?
|
Fossils are remains and impressions of earlier life on Earth. An environment favourable to the growth and later preservation of the organism is needed.
|
|
|
What is needed for fossilisation of a certain organism to occur?
|
1. Hard parts -
Or 2. Quick burial - to prevent weathering, and consumption |
|
|
What happens to hard body parts over the period of fossilisation?
|
They are petrified (replaced by minerals like calcite, quartz, pyrite.)
|
|
|
How might a paleontologist find fossils?
|
If the fossil is uplifted in mountains by crust movement and the ground is eroded.
|
|
|
What is relative age determination? Who's law does this rely on?
|
Where fossils are compared by their position in the stratigraphic column. Steno's law of superposition
|
|
|
What is radio carbon dating?
|
A small amount of natural carbon is C14 (a radioactive isotope). This is taken in by organisms in their life. Radiocarbon decays at a known rate. Only effective for objects less than 50000 years old
|
|
|
What 4 ways can relatedness with a common ancestor be determined?
|
1. Embryology
2. Homologous structures 3. Vestigal organs 4. Biochemical studies |
|
|
What is embryology?
|
The study of growing fetus of each species to analyse similar physical appearances. For example, rudimentary gills in vertebrae.
|
|
|
What is homologous structures and give an example?
|
Similar physical structures for example a pentadactyl limb.
|
|
|
Vestigal organs?
|
Body parts that an organism does not use but are similar to those used by another species.
|
|
|
Biochemical analysis?
|
Looking at chromosome makeup to see similar gene patterns. More advanced species often have most of the DNA of less advanced species.
OR DNA hybridisation where DNA is combined, the amount of heat required to separate them indicates how related the species are. |
|
|
What is something that may seem to be homologous structures but is not? What do they show instead of relatedness?
|
Analogous structures. Convergence instead of relatedness
|
|
|
What is genetic drift? How can this be manifested?
|
A subject in biogeography that refers to a genetic change that occurs by chance rather than natural selection. If a mountain range rises between populations.
|
|
|
What is macroevolution?
|
A new species being formed from minor evolution.
|
|
|
What is allopatric speciation?
|
Allopatric speciation is where a species arises from isolation from other species. This may occur due to competition, natural forces (extreme weather)
|
|
|
What is sympatric speciation? What organism does this commonly happen to?
|
A new species forms in the same area as the old. Polyploid plants because they are genetically isolated and must reproduce with themselves.
|
|
|
What are prezygotic isolating mechanisms?
|
Those that prevent successful breeding of two separate species. E.g behavioural patterns, attracting a mate, occupation of different habitats
|
|
|
What are postzygotic isolating mechanisms?
|
Infertile offspring, non-developing fetus, Low survival rates of offspring
|
|
|
What is gradualism?
|
The gradual change in genetic makeup of species over time to form gradual changes in phenotype that make separate species gradually more obvious.
|
|
|
What is punctuated equilibrium?
|
The species are in a state of equilibrium for a long period of time and then a sudden change in external influences causes a sudden jump in evolution.
|
|
|
What is divergence and speciation?
|
The gradual change of an isolated population of one species into another that can no longer interbreed with the original species to form viable offspring.
|
