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Biology - Week 3
DNA structure and Classification processes
Terms in this set (37)
Define the term clade
A clade is a section of a phylogenetic tree. A group of organisms that consists of a common ancestor and all lineal descendants.
What are the common assumptions of cladistics?
How do you interpret cladograms to infer the evolutionary relatedness between groups of organisms?
Every time an species passes a branch with a characteristic on it (e.g. scales) it adopts those characteristics and becomes a new species.
Define biological species and phylogenetic species? What are the limitations of different definitions of species?
A biological species is a group of organisms that can reproduce with one another in nature and produce fertile offspring.
limitation: if you have an asexually reproducing species. Extinct organisms (can't say who they are reproducing with).
A phylogenetic species is groups organisms by the smallest set of individual organisms that share a common ancestor.
limitation: it's prone to mutation over time. If mutations occurred you have more species. Therefore, we overestimate the number of species.
Identify one example of an interspecific hybrid and why they cant produce offspring?
A mule (donkey x horse)
They can't produce offspring because they are infertile and therefore arent a species.
What is predation?
An interaction in which one organism captures and feeds on another organism
What is competition?
the struggle between organisms to survive as they attempt to use the same limited resources
What is symbiosis?
two species living together. It can be mutualistic, commensalistic, parasitic, and ammensalistic.
What is a disease?
What ways can you classify and name an ecosystem?
Classification of ecosystems could be based on:
- the Holdridge life zone classification scheme
- Specht's classification system
- ANAE classification system
- EUNIS habitat classification system.
Holdridge life zone classification scheme
global bioclimatic scheme for the classification of land areas
What is Specht's classification system?
Based on canopy cover and the height and form of the dominant vegetation.
ANAE classification system
framework for classifying different aquatic ecosystems and habitats including rivers, floodplains, lakes, palustrine wetlands, estuaries and subterranean ecosystems.
EUNIS habitat classification system
How is the process of classifying ecosystems an important step towards effective ecosystem management?
Old growth forests
Describe the process of stratified sampling
What is the purpose of stratified sampling?
It is to either:
Estimate a population
environmental gradients and profiles
Used to consider different areas (or strata) which are identified within the main body of a habitat.
Stratified sampling site selection?
Stratified sampling methods (1st step)
Random sampling and systematic sampling
What is Random sampling?
random number generator to divide a grid and pick a rid square
e.g. sampling energy one metre. Not very good for something moving around
Stratified sampling techniques (2nd step)
How does stratified sampling minimize bias?
size and number of samples
noting associated precision
Stratified sampling methods of data presentation and analysis?
What is the role of helicase in the process of DNA replication?
Enzyme that opens DNA by splitting hydrogen bonds. (Refer to direction of replication)
What is the role of DNA polymerase in the process of DNA replication?
Occurs after helicase unwinds the DNA.Reads from 3' to 5' and synthesises a new daughter stand from 5' to 3' direction (5' on 3' and 3' on 5') from free nucleotides in the nucleus.
What is the structure of DNA?
Has complementary base pairing
Weak base specific hydrogen bonds between DNA strands
What is the difference between prokaryotic DNA and eukaryotic DNA?
- Stored in the cytoplasm in the form of a nucleoid.
- Prokaryotes contain circular DNA.
- do not have membrane-bound organelles.
- older and simpler than eukaryotic
- stored in the nucleus
- Eukaryotic DNA is linear, compacted into chromosomes by histones
- Eukaryotic cells contain mitochondrial DNA in addition to nuclear DNA.
- it is double-stranded
- have membrane-bound organelles
Describe deoxyribose nucleic acid?
- Double stranded molecule (helix)
- Bound to proteins (histones) in chromosomes in the nucleus
- Has unbound circular DNA in the cytosol of prokaryotes and in the mitochondria and chloroplasts of eukaryotic cells.
- Nucleotide: consists of phosphate, sugar, and nitrogenous base (A-T, C-G)
- Long strand of nucleotides
- Single stranded
- base change (A-U, C-G)
- Types of RNA include mRNA (messenger/transcription-->copying DNA), tRNA (transfer - translating from language of nucleic acids to amino acids (proteins)), rRNA (ribosomal) and other RNA (e.g. microRNA, gene regulation).
Describe the process of translation
The purpose is to change from the language of Nucleic acid to amino acid. The protein-making machinery, called the ribosome, reads the mRNA sequence and translates it into the amino acid sequence of the protein, The ribosome starts at the sequence AUG, then reads 3 nucleotides at a time. Each 3-Nucleotides codon specifies a particular amino acid. The tRNA made of the anticodon can bind to the codon on the mRNA. The stop codons (UAA, UAG, UGA) tell the ribosome that the protein is complete and stops last tRNA from producing amino acid.
Describe the process of transcription
3 steps - Initiation, elongation, termination
1 (I). Enzyme RNA polymerase binds to the site on DNA at the start of a gene. It is helped by transcription factors.
2 (E). RNA polymerase separates DNA strands and synthesizes a complementary RNA copy from the antisense (non-coding) DNA strand.
3 (T). When the RNA polymerase reaches the termination site of the gene, RNA polymerase will detach from the DNA molecule; RNA detaches from the DNA and double helix reforms. This occurs in the nucleus.
Explain the classification of organisms according to symbiosis
parasitism - one species is harmed and the other is benefitted
mutualism - both species benefit
commensalism - one species is benefitted and the other is not harmed.
ammensalism - one species is unaffected and the other is harmed
predation - one of them acts as a predator that captures and feeds on the other organism that serves as the prey.
Biological classification can be hierarchical or based on different levels of similarity. What are the different types of similarity?
- Physical features
- methods of reproduction
- molecular sequences
What is the classification system for the methods of reproduction? Explain them...
K-strategists - long parental care, longer life span, fewer offspring, longer life span.
R-strategists - short parental care, shorter life span, more offspring, shorter life span.
asexual and sexual???
What is the classification system for molecular sequences?
Molecular phylogeny - also called cladistics
What is the classification system for similarity if physical features? Explain
- Kingdom (keep)
- Phyllum (pond)
- class (clean)
- order (or)
- family (frog)
- genus (gets)
- species (sick)
classify things into 5 kingdoms:
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