Mind Map by tiasabs , updated more than 1 year ago
Created by tiasabs over 4 years ago


Mind Map of Topic 3.2 Chromsomes in Gentics chapter of IB Biology

Resource summary

1 Bacterial chromosomes
1.1 Prokaryotes
1.2 single circular DNA molecule
1.3 one chromosome
1.3.1 all genes needed for life
1.4 not associated with proteins - naked DNA
1.5 single copy of gene except cell division
2 Plasmids
2.1 in some prokaryotes
2.2 Eukaryotes don't have
2.3 small extra DNA molecules
2.4 circular; naked
2.5 contains few genes not necessary for life
2.6 not replicated at the same time or rate
2.7 copies can be transferred
2.8 can cross species barrier
2.8.1 released at death and absorbed by new cell
2.8.2 natural
2.8.3 artificially possible
3 Differences between chromosomes
3.1 diff. chromosomes carry diff. genes
3.2 length
3.3 position of centromere
3.4 at least two different types
3.5 different gene sequnece
4 Eukaryote chromosomes
4.1 linear DNA molecules
4.2 histone proteins
4.2.1 globular in shape
4.2.2 wider than DNA
4.2.3 many with DNA wound around
4.2.4 adjacent separated by short DNA stretches
4.3 made of DNA and proteins
5 Homologous chromosomes
5.1 same gene sequence but not alleles
5.2 allows species to interbreed
6 Haploid nuclei
6.1 one chromosome of each pair
6.2 one full set of chromosomes
6.3 gametes have it
7 Diploid nuclei
7.1 pairs of homologous chromosomes
7.2 two full sets of chromosomes
7.3 zygote has it
7.4 all cells except gametes are diploid
7.5 two copies of each gene
7.6 dominant allele prevents effects of recessive mutation
7.7 more vigorous organisms
8 Chromosome numbers
8.1 characteristic feature of species members
8.2 only same numbers can interbreed
8.3 can change due to evolution
8.3.1 rare and unlikely
9 Sex determination
9.1 by sex chromosomes
9.1.1 X chromosome large centromere near middle all humans have at least one females have 2 one passed on in egg cell
9.1.2 Y chromosome smaller centromere near end one in males SRY or TDF
9.2 autosomes
9.2.1 chromosomes that don't determine sex
9.3 half sperm have X; half have Y
9.4 sex determined at fertilization
10 Karyograms
10.1 shows chromosomes of organisms
10.1.1 homologous pairs
10.1.2 decreasing lengths
10.2 visible in cell in mitosis
10.2.1 clearest: metaphase
10.3 some stains - distinctive banding on diff. chromosomes
10.4 arranged in pairs by length
10.4.1 done manually before
10.4.2 now digital
10.5 micrograph taken of dividing cells
10.6 types distinguished by:
10.6.1 position of centromere
10.6.2 banding pattern
10.6.3 size/length
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