null
US
Sign In
Sign Up for Free
Sign Up
We have detected that Javascript is not enabled in your browser. The dynamic nature of our site means that Javascript must be enabled to function properly. Please read our
terms and conditions
for more information.
Next up
Copy and Edit
You need to log in to complete this action!
Register for Free
5254636
CfE Higher Biology - Unit 1
Description
Mind Map on CfE Higher Biology - Unit 1, created by Claire Purves on 26/04/2016.
No tags specified
higher
Mind Map by
Claire Purves
, updated more than 1 year ago
More
Less
Created by
Claire Purves
over 8 years ago
1183
3
0
Resource summary
CfE Higher Biology - Unit 1
Key Area 1 - DNA Structure
Genetic info is stored in the base sequence of DNA
Genotype is determined by the sequence of bases
Nucleotide - deoxyribose sugar, phosphate, base
Sugar phosphate backbone - phosphate joins carbon 5 on sugar and carbon 3 on other sugar
Hydrogen bond between bases
Double helix, antiparallel
Prokaryotes - circular chomosomal DNA & plasmids, no membrane bound nucleus
Eukaryotes - linear chromosomes in nuclei, tightly packaged with associated proteins
Mitochondria and chloroplasts have circular chromosomes
Key Area 2 - DNA Replication
Required so that each daughter cell has an identical copy of DNA
Important to help give growing cells exact copies
Requires the DNA (template), free DNA nucleotides, ATP, enzymes & primers
Enzymes: DNA polymerase - adds complementary nucleotides and Ligase - joins fragments together
Primer - allows DNA polymerase to bind
Primers form at the 3' end
1. DNA unwinds, hydrogen bonds break
2. DNA polymerase adds nucleotides to the 3' end
3. On the leading strand (beginning with 3'), a primer binds to the DNA
4. DNA polymerase adds nucleotides to the 3' end
PCR (Polymerase Chain Reaction) - replicate DNA quick in a lab
1. Heated (approx 90 degrees) to break the hydrogen bonds, seperate strands
2. Cooled (approx 60 degrees) to allow the primer to anneal to its target sequence
3. Heated (approx 72 degrees) so heat-tolerant DNA polymerase can add nucleotides to the primers at 3' end. Then it repeats.
Used for forensics and the study of evolution
5. Fragments of DNA are joined together by ligase.
Key Area 3 - Control of Gene Expression
Phenotype is determined by the proteins produced as a result of gene expression
Gene expression is controlled by the regulation of transcription and translation
Gene expression is influenced by intra- and extra-cellular factors
Amino acids - peptide bonds, folded, hydrogen bonds
RNA: one strand, uracil replaces thymine, ribose sugar
mRNA - carry copy of DNA to ribosome tRNA - transports AA to ribosome to be translated
Transcription
In nucleus
RNA polymerase unwinds DNA
RNA nucleotides form a primary transcript
Introns - non-coding Exons - coding
Introns are removed by RNA splicing
Translation
Mature mRNA goes to cytoplasm to find a ribosome
tRNA carries an amino acid
tRNA has an AA attachment site, anticodon
Anticodons on tRNA pair with codons on the mRNA
Peptide bonds form between amino acids, polypeptide chain
Post-translational modification: cutting and combining polypeptide chains, adding phosphate or carbohydrate groups
Key Area 5 - The Structure of the Genome
Genome of an organism is the complete set of genetic info encoded in its DNA that can be inherited by offspring
Genes - DNA sequences that code for protein
A genome is made up of genes and other DNA sequences that don't code for proteins
Most of the genome consists of non-coding regions
Regulation of transcription by turning genes on or off
Transcribed but not translated (e.g. rRNA, tRNA)
No known function
Key Area 7 - Evolution
Changes to organisms over time mainly caused by natural selection
Vertical inheritance - from parent to offspring (asexual and sexual)
Horizontal inheritance - prokaryotes, rapid evolutionary change
Prokaryotes and viruses transfer genes horizontally into the genomes of eukaryotes
Natural selection - non-random increasein frequency of DNA sequences that increases survival
Sexual selection - natural selection of characteristics that increase reproductive success
Selection pressure
Stabilising - favours the middle characteristics in a range of variation
Directional - favours an extreme characteristic away from the middle
Disruptive - favours two extreme characteristics at the expense of the middle
Genetic drift - random increase or decrease to DNA sequences
Happens in small populations by chance events , neutral mutation, colonisation, founder effect
Founder effect - groups become isolated from the main group
Speciation - generation of a new biological speciesby evolution due to isolaion, mutation and selection
Allopatric - geographical barriers (mountains, oceans)
Sympatric - ecological and behavioural barriers
Hybrid zones form in regions where frequent interbreeding between two species occur
Key Area 8 - Genomic Sequencing
To compare sequence data, computer and statistical analyses (bioinformatics) are required
Phylogenetics - study evolutionary relatedness among groups of organisms
Sequence divergence - used to estimate time since lineages diverged
3 domains of life: bacteria, archea, eukaryotes
Analysis of a persons genome could lead to personalised medicine (pharmacogenetics)
Difficulties in relating individual genome data to treatments and in the complex nature of many diseases
Comparing genes from different species reveals that many genesare highly conserved across different organisms
Key Area 4 - Cellular Differentiation
Cellular differentiation - cell develops more specialised function
Meristems are regions of unspecialised cells in plants
Can divide and differentiate into specialised cells
Apical: root tip and shoot tip Lateral: between phloem and xylem
Stem cells are unspecialised somatic cells than divide (self-renew) and differentiate into specialised cells
Embryonic stem cells can differentiate into all cell types (pluripotent)
Adult stem cells have a narrower differentiation potential, genes are switched off (multipotent)
Needed for growth, repair and renewal of tissues
Ethical issues regarding stem cells
What's more important: Our duty to prevent disease or respect the value of human life?
Should we allow healthy people to use stem cells to change body characteristics?
Stem cells might be bought and sold illegally and treatment could cost money
Key Area 6 - Mutations
Mutation are random, rare changes to DNA sequences (ROLF)
Single gene mutations - alter DNA nucleotide sequence (DIGS)
Substitution - A nucleotide is removed and replaced by another. Minor impact (missense). Major impact if production or loss of a stop codon (nonsense)
Insertion - Add a nucleotide. Deletion - removal of a nucleotide. Frame-shift mutations, all amino acids are affected
Splice-site - introns are left in the mature mRNA leading to an altered protein
Regulatory sequence mutations can alter gene expression
Mutations are important in evolution
Chromosome mutations: affect number and structure of a chromosome (DICTD)
Duplication - extra copies of genes on a chromosome. Can be detrimental or important to evolution
Deletion - detached genes are lost completely (cri du chat syndrome)
Translocation - detached genes join onto another chromosome (1 type of Down syndrome)
Inversion - Chromosome breaks in 2 places and rotates 180. Results in infertility as gametes can't be formed
Polyploidy - possession of extra sets of chromosomes due to errors during the seperation of chromosomes during cell division
Banana, potato, strawberry
Media attachments
b15ec530-f5a4-4977-9eab-897693dcdb0a.PNG (image/PNG)
Show full summary
Hide full summary
Want to create your own
Mind Maps
for
free
with GoConqr?
Learn more
.
Similar
Business Studies Unit 1
kathrynchristie
GCSE AQA Biology - Unit 1
James Jolliffe
GCSE AQA Physics - Unit 1
James Jolliffe
Physics 1
Peter Hoskins
AQA GCSE Biology B1 unit 1
Olivia Phillips
Cell Transport
Elena Cade
Business Studies - AQA - GCSE - Types of Ownership
Josh Anderson
Computer Systems
lisawinkler10
Summary of AS Psychology Unit 1 Memory
Asterisked
Memory - AQA Psychology Unit 1 GCSE
joshua6729
Business Studies Unit 1
emily.mckechnie
Browse Library