B-6 Inheritance, DNA and evolution Flashcards
1
Q
- What is DNA
A
- DNA is the chemical that that genetic material is made up of
- Coded information- act as instructions
- ## Inherited characteristics
2
Q
- What is DNA’s structure
A
- Two strands twisted together in double helix
3
Q
- What are chromosomes
A
- Long molecules of DNA
- Come in paris
4
Q
- What are genes
A
- Small sections of DNA on chromosomes
- ## Each gene codes for sequence of amino acids that make a specific protein
5
Q
- What is a genome
A
- Entire genetic material in an organism
- Scientists have worked out the human genome
6
Q
- What is the significance of working out the human genome
A
- Working out common ancestors and migration patterns
- Inherited disease gene cause
- Disease and genes linked to it
7
Q
- What is sexual reproduction
A
- Joining- fusing- of male and female gametes
8
Q
- What forms of sexual reproduction is seen in animals and plants
A
- Animals- Sperm and egg cells
- Plants- Pollen and egg cells
9
Q
- Why are offering in sexual reproduction not identical
A
- There is a mixing of genetic material which leads to a variety of offspring
10
Q
- What is the difference between mitosis and meiosis
A
- Mitosis leads to identical cells forming
- Meiosis leads to non-indeoitcal cells
11
Q
Why do gametes have half the number of chromosomes
A
- Gametes are produced by meiosis and only have one cope of each chromosome
- So when gamut fusion takes place the full fusion takes place
- Ceel devisor takes place to make them have half the number of chromosomes
12
Q
- What is a gamete
A
-Sex cells with half the number of cells than the original
13
Q
- What are the stages in meiosis - extra knowledge
A
- Copies the genetic material are made
- Cell divides once after alining along centre
- The cell is pulled apart and each new cell has a different combination of cells
- In the second devising the chromosomes are pulled apart to the poles
- They split again and four different cells are made
14
Q
- What happens when a cell divides to form gametes
A
- Copies of gametes are made
- Cell divides twice to form gametes - 4- each with single set of chromosomes
- All gametes are genetically different
15
Q
- What is an allele
A
- Different form os a gene
16
Q
- What is a dominant allele
A
- If a dominant gene is present it will express itself regardless of other allele
17
Q
- What is a receive allele
A
- Requires two receive alleles to be present to be expressed
18
Q
- What is meant by homozygous
A
- An organism or gene that has two of the same alleles
19
Q
- What is meant by heterozygous
A
- If two alleles are different
20
Q
What is a genotype
A
- Combination of alleles you have
21
Q
- What is a phenotype
A
- Your expressed characteristics- determined by your genotype
22
Q
- What characteristics are controlled by a single gene
A
- Fur in mice
- Red-green colour blindness
23
Q
- How do alleles work
A
- Alleles work at a molecular level to develop expressive phenotype
24
Q
- Explain the genetics of a Tt gene combinations
A
- TT- homozygous dominant- T expressed
- tt- homozygous recessive
- Tt or tT- Heterozygous dominate- T expressed
25
What are genetic disorders
- Some disorders are inserted this is caused by inheritance of certain alleles
26
- What is polydactyl disease
- Inherited disorder
- Having extra fingers or toes
- Caused by dominant alleles
27
- What is the likelihood of getting polydactyl disease
- With one parent having allele- 50%
| - With two parents having allele- 75%
28
- What is cystic fibrosis
- Disorder of cell membrane
- Caused by recessive allele
- Inherited disorder
29
- What is the likelihood of getting cystic fibrosis
- Both parents have to be carriers- 25%
30
- What are arguments for genetic screening
- Help stops suffering
- Money saved- less treatment
- Laws are in place to stop it going to far
31
- What are arguments against embryonic screening
- Prejudice against "unwanted"
- Everyone will want it to get perfect baby
- Expensive
32
- How is sex decided
- Ordinary human body has 23 sets of chromosomes
- one pair determine sex
Male- XY Female- YY
- 50% chance of either
33
- What is variation
- Different characteristics within a population
| - Caused by both environment and genetics
34
- How can environment impact organisms
- An example is a plant- one with lots of light will grow luscious and green. One in a dark room will grow tall and spindly
35
- What are mutations
- Change in genetic information
- Occur continuously- very rarely will they lead to change in phenotype
- Little effect on genetic code
36
- How can environmental change lead to new phenotypes
- IF a new phenotype makes an organism more suited to an environment it will happen more rapidly by natural selection
37
- What is evaluation
- Evolution is the change in inherited characteristics in a population over time through a process of natural selection
- May result in new species
38
_ What is the theory of evolution
- All species living have developed from simple life forms over 3 million years ago
39
- What are the steps in natural selection
- Organisms with desirable characteristics are more likely to survive
- MORe likely to reproduce
- Those without desired characteristic die off
- Over time desirable characteristic becomes more and more prominent
40
How do two species form from one
- IF one species becomes so different that they can no longer reproduce to produce fertile offspring they are 2 species
41
- What is selective breeding
- Process which humans breed animals and plants for particular genetic characteristics
- Humans have been doing it for thousands of years
42
-What are examples of selective breeding
- Animals that have more meet or milk
- Crops with disease resistance
- Dogs with gentle nature
- Decretive plants- large flowers
43
What are the steps in selective breeding
- Choose parents with desired characteristic
- Breed
- Breed offspring with desired characteristic
- Reproduce
44
What is the drawback to genetic engineering
- Reduction in gene pool- inbreeding- genetic disease
45
What is genetic engineering
- A process that involves the genome of an organism and introducing the gene of an organism with the desired characteristic
46
- What are examples of GE
- Plant crops have been GEd to make GMOs to produce higher yield and be resistant to disease
- Bacteria have been Ged to produce insulin
47
- What are the pros of GE
- Increased crop yield
- Nutrient engineering- Golden rice- blindness - Beta carotene
- Already ahppening- no bad effects yet
48
What are the cons to GE
- Gm crops reduce the population of wild flowers around it- in turn biodiversity reduced
49
- What are the steps in GE
- Enzyme used to isolate required gene
- Isolated into vector usually a virus or plasmid
- Vector then used to insert it into required cell
- Genes transfered to cells of animals, plants or micro-organisms in early stages- allow to develop with it
50
- What are fossils
- Remains of organisms from millions of years ago found in rocks
- We can earn about the extent of change
51
- How are fossils formed
- Parts of organisms not decaying as not all conditions were present
- Parts of organisms replaced by minerals
- Preserved remains from organisms
52
- What issues with fossils
- Uncertainty about starts earth as most organisms were soft bodied and left little remains
53
-What is extension
- No living individual of a species is left
54
- What are the causes of extinction
- Environmental changes
- New predator
- New disease
_ Can't compete for food
- Catastrophic event
55
What is resistant bacteria
- Bacteria that is now resistant to Antibiotics
| - Bacteria as it can evolve at faster rate as it reproduces rapidly
56
- What are the steps in forming resistant bacteria
- Mutation occurs
- Strain is resistant when rest are killed off
- Reproduce and become dominant form
- No treatment and now immune
57
- What is MMRA
- Resistant form of bacteria
58
- How can resistant bacteria be reduced
- Only prescribed when needed
- Finnish full course of antibiotics
- Agricultural use limited
59
- Why can new medication not be made for resistant bacteria
- Development of antibiotics is expensive and cannot be done at the same rate as the development of resistant strains
60
- What was the original form of classification
- Linnaeus system
| - Kingdoms- phylum-class-order-family-spices
61
How does classification change
- With more knowledge
62
- What was the system found in the 1990s
- Woes' system,
- Archaea- Extremophiles-primitive
- Bacteria- True bacteria
- Eukyrots- Fungi, plants and animals- with a true nucleus
63
What are evolutionary trees
- Used to show how they believe organisms are related
| - Fossil data is used to map extinct organisms
