Bio Sem 2 Unit 2 Exam Rev Flashcards
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The structure of DNA
Phosphate group
Deoxyribose sugar
Nitrogenous Bases - Guanine, Cytosine, Thymine, Adenine
Name the 3 distinct chemical components in the nucleotide
A sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base.
Understand the difference between DNA and RNA
DNA has a deoxyribose sugar while RNA has a Ribose sugar
DNA is a double helix while RNA is a single-strand
DNA has Thymine while RNA has Uracil
The general steps to produce a protein from DNA
- Transcription - DNA is read and transcribed by the RNA polymerase into a single-strand RNA with Thymine being changed to uracil, producing pre-mRNA
- RNA editing - Introns are removed, Exons are spliced together - produces mRNA
- Translation - The mRNA is translated by the tRNA into a polypeptide protein chain
What is the DNA and RNA base pairing rules
DNA
Adenine = Thymine
Guanine = Cytosine
RNA
Adenine = Uracil
Guanine = Cytosine
If DNA sequence is:
ACCAAACCGAGT
Find out the mRNA sequence
UGGUUUGGCUCA
What are the functions of
rRNA, mRNA, tRNA
rRNA - Makes up 60% of the ribosome; site of protein synthesis
mRNA - Carries the code from DNA that specifies amino acids used in translations (mesenger RNA)
tRNA - Carries a specific amino acid to ribosome, based on its anticodon to mRNA codon
Define Transcription, where and how does it occure?
Transcription is the process in which DNA is transcribed into a single strand pre - mRNA
All this happens in the nucleus of a cell
Define RNA processing, where and how does it occure
RNA processing or RNA editing is when the RNA polymerase takes in the pre-mRNA and removes the introns and splices together the exons to create a mature mRNA.
This happens in the nucleus of a cell - Transcription
How does nucleic acids encode the instructions to make proteins
The mRNA sequence used as a template to assemble the chain of amino acids that form a protein
What is the difference between a triplet, codon, and anticodon?
Anticodon - A section of 3 bases that are from the tRNA
Codon - A section of 3 bases that are from the mRNA
Triplet - A section of 3 bases
Define Gene structures
- Exons
- Introns
- Promoter
- Operator regions
Exons - Parts of the pre-mRNA that is kept and spliced together to form the mature mRNA
Introns - Parts of the pre-mRNA that is removed (unecessary)
Promoter - section of DNA where RNA polymerase binds and transcription begins
Operator - section of DNA where proteins that control transcription bind
Describe the benefits of gene regulation e.g lac operon
Allows cells to react quickly to changes in their environments.
What are the components of a protein
- polypeptide chain of amino acid monomers
Explain the connection between DNA, Genes, Chromosomes and Alleles
Chromosomes are a threadlike structure of nucleic acids and protein, carrying genetic information (DNA) in the form of genes
Gene is a section of DNA that carries the code to make a protein - determines the trait
Alleles are alternative forms of gene
Define homologous chromosome
Pairs of chromosomes that have same genes and chromosome size
Define Sister chromatid
Identical copies of a chromatid that are held together by centromere
Define Centromere
The middle of the Chromosome that holds the chromatids together
Define Locus
The location of one gene on a chromosome
Loci - multiplie genes on a chromosome
The difference between genes, alleles and genomes?
Genome is all of the DNA in an organism, gene is a section of DNA, Alleles are different forms of genes
Difference between autosomes and sex chromosomes
Autosomes are chromosomes that determine the traits of an organism while sex chromosome determines the gender of an organism
How do we read a Karyotype
First 22 sets of chromosomes are autosomes
Last set (23rd) is sex chromosome
Describe the 5 main types of asexual reproduction
- Binary fission - bacteria cells - splits from 1 cell to 2 cells once
- Budding - Small bud grows out of parent, Two different sized structures made with identical DNA, Bud can breaks off and grow into new organism
- Fragmentation - A piece of an organism breaks off and forms an individual organism containing the same DNA
- Vegetative propagation - occurs in plants, in which a new plant grows from a fragment or cutting of the parent plant
- Sporogenesis (Spore Formation) - The process of formation of spores - has same DNA as parent spores
List 3 Advantages and Disadvantages of asexual reproduction
Advantages of asexual reproduction
- Increased speed in population growth
- offsprings are identical therefore fine-tuned to it’s environment
- Does not require much energy due to not needing to find a mate
Disadvantages of asexual reproduction
- Lacks the ability to adapt to new environment
- Disease may affect all the individuals in a population.
- The organisms produced have shorter lifespans.
Define sexual reproduction
Involves the fusion (fertilisation) of two haploid gametes to form a single, genetically unique diploid cell, zygote.
List 3 Advantages and Disadvantages of sexual reproduction
Advantages of Sexual reproduction
- Increase genetic diversity
- Improve disease resistance by promoting the presence of different alleles
- Combining the genetic material from two gametes reduces the chances of an offspring inheriting a genetic disorder that might be carried by one parent.
Disadvantages of Sexual reproduction
- The time, energy, and resources it takes to attract and find a mate
- Risk of transferable diseases associated with sexual intercourse
- The risk of losing offspring to outside influences such as embryo damage.
Define diploid, haploid, gametes and somatic cells
- Diploid - A cell that contain two sets of each chromosome
- Haploid - The presence of a single set of chromosomes in an organism’s cells
- Gametes - Sex cells e.g: sperm and egg
Somatic cells - Normal body cells
List and describe the process of reproductive cloning techniques (Embryo splitting and Somatic cell nuclear transfer [SCNT])
SCNT
1. Somatic cell from one animal is taken out as well as 1 egg cell from a egg cell donor
- Enucleation removes the nucleus from the egg cell to prevent it’s DNA from contaminating the DNA from the somatic cell. At the same time the nucleus from the somatic cell is removed
- The nucleus from the somatic cell is than injected into the egg cell which has no nucleus (done w electricity)
- The new fused egg cell with the nucleus is than placed into a surrogate mother
Embryo splitting
1. An embryo is split into two at an early stage (6-8 cells)
to develop twins.
- Each individual develops as an independent embryo
and develop into genetically identical offspring.
Artificial embryo splitting
Done artificially, the split embryos are implanted into surrogate mothers until birth.
Stages of meiosis
Prophase 1 - Chromosome condenses, breakdown of nuclear envelope, crossing over occurs
Metaphase 1 - Homologous chromosome lines up at equator
Anaphase 1 - homologous chromosome move to opposite poles
Telophase 1 & cytokinesis - Chromosomes gather at poles of each cell and cytoplasm divides
Prophase 2 - New spindle fibers form around chromosomes
Metaphase 2 - Chromosomes line up at equator
Anaphase 2 - Centromeres divide, chromatids move to opposite poles
Telophase 2 & cytokinesis - Nuclear envelop forms around chromosomes, cytoplasm divides
Define Crossing over
Homologous pairs of chromosomes come together before meiosis begins
The chromosomes match up with their homologous pair, and swap sections of their chromosomes.
Leading to genetic diversity by mixing up the genes
Define independent assortment
The homologous pairs of chromosomes line up in random orientations at the middle of the cell as they prepare to separate leading to genetic diversity by mixing up the genes
Describe the importance of genetic diversity in a population
Genetic diversity is needed in a population as it increases the Gene pool of different traits therefore leads to certain groups of traits being more favourable than others
Difference between meiosis and mitosis
Mitosis only splits once while meiosis splits twice
meiosis is usually in sexual reproduction while mitosis is in asexual reproduction.
Difference between genotype and phenotype
Genotype is the genetic make-up of a person while phenotype is the visible trait presented through features
Difference in codominance and incomplete dominance
Codominance - Mix of genes and visual features of both parents
Incomplete dominance - A blend of genes and visual features of both parents
Pattern of inheritance
Autosomal
Sex-linked
Dominant
Recessive
Autosomal - affects both male and female equally
Sex-linked - Affects mostly females
Dominant - is seen in all offsprings
Recessive - Comes and goes from generation to generation (usually re-appears in the third generation)
Define consequence based approach
Maximise positive outcomes while minimising negative effects
Define rules based approach
Follow set rules and responsibilities, with less regards for the consequences that may result
Define virtues based approach
Emphasise the moral nature of the individual, and provide guidance as to the behaviours a morally good person would hope to achieve
Define integrity
Trustworthy and Honesty
Define respect
Acknowledgment of the intrinsic value of living things, and considers the welfare, beliefs, customs, and cultural heritage of both the individual and the collective
Define justice
Fair consideration of competing claims, and ensures that there is no unfair burden on a particular group from an action
Define beneficence
Maximise benefits when taking a particular position or course of action
Define non-maleficence
Discourages causing harm – or when harm is unavoidable ensuring positives outweigh the negatives
Define antigen
Any molecule that can produce an immune response
Define self antigen
Surface molecules that that identify them as self.
Major histocompatibility complex (MHC) proteins.
Define non-self antigen
Antigens that originate from outside the host’s body.
Define allergen
When the immune system reacts incorrectly to a molecule that is not a pathogen
What is the importance of self and non-self antigens in immune function?
Self antigens allow for recognition of own body cells
Non-self antigens allow for recognition of foreign cell and elimination of foreign cell
General features of the six different types of pathogens
Parasites - largest pathogen - worm-like
Protozoa - cell pathogen
Fungi - groups of single cells
Bacteria - Cell with cell membrane and wall as well as a flagella - reproduces through binary fission
Viruses - non-living, only has cell wall and RNA
Prions - misshaped proteins that causes other proteins to misshape (smallest pathogen)
Difference between cellular and non-cellular pathogens
Cellular pathogen- living, has membrane bound organelles and can reproduce by itself
Non-cellular - non-living, has no membrane bound organelles or no organelles at all, can not reproduce by itself
Difference between first, second and third lines of defence
First - Innate immunity
- Barriers to prevent pathogens from entering (skin, mucous membrane)
Second - Innate immunity
- Mostly involves immune cells and proteins to nonspecifically recognize and eliminate any pathogen that enters the body (Phagocytes, antimicrobial proteins , inflammatory response, Fever)
Third - Adaptive immunity
- adaptive immune system develops as we encounter antigens throughout our lives, adaptive immune system is slower to activate (days) (Lymphocytes, antibodies, memory cells)
Define chemical, physical and microbiological barriers
- give examples in humans
Chemical - Barriers with chemical substances that make the environment hard to live in for pathogens - Stomach acid, enzymes in saliva, antibacterial proteins
Physical - Barriers that block or hinder pathogens from entering an organism - Skin, mucus secretions
Microbiological - Non- pathogenic bacteria (flora) prevents the growth of other bacteria due to competition - bacteria on skin and in lower intestines, non-pathogenic organisms in the vagina
Define phagocytes
cells that do phagocytosis, a process in which they consume and destroy pathogens and foreign material. This is a process of the innate immune system.
3 types of phagocytes
- neutrophils
- macrophages
- dendritic cells
Describe the steps of the inflammatory response
- Damaged tissues attract mast cells which release histamines which defuses in the blood vessels
- Histamine dilutes blood vessels and becomes leaky, complement proteins leave vessels and attract phagocytes
- Blood plasma and phagocytes move into infected tissue from the vessels
- Phagocytes engulf bacteria and dead cells
- Histamine and complement signaling cease, phagocytes no longer attracted
- Wound heals from white blood cells and platelets producing growth factors
3 main functions of complement proteins
Membrane attack - rupture of the cell wall of bacteria
Phagocytosis - enhance phagocytosis
Inflammation - by attracting macrophages and neutrophils
What are the key similarities and differences between the humoral and cell mediated pathways of adaptive immunity
Differences - Humoral immunity produces antigen-specific antibodies, whereas cell-mediated immunity does not
Similarities - Both humoral and cell-mediated immunity are active immunities
Be able to draw a diagram of an antibody, label its antigen-binding site
Describe how vaccination works
Vaccination works by providing a dead or weakened version of a pathogen which triggers the immune system, this immune response allows the body to remember the pathogen in cause in the future the real pathogen comes to invade the body
Define and identify dependent, independent and controlled variables
Independent variable - A variable that you can manipulate
Dependent variable - A variable that is changes due to the independent variable
Controlled variable - A variable that is set by you and does not change / can not be manipulated
Define and identify experimental control or control group
allow the experimenter to minimize the effects of factors other than the one being tested.
