bl2001 astrid

euchromatin

contains genes

less condensed

at chromosome arms

gene rich

heterochromatin

doesn’t contain genes, contains highly repetitive sequences

highly condensed

at centromere and telomeres

gene poor

sources of non coding dna

pseudogenes

introns

tandem repeats

transposable elements

promoter

dna sequence that controls the initiation of rna transcription

aim of human genome project

to build a comprehensive parts list of functional elements in the human genome

what are transposable elements

mobile genetic elements

where do colour mutations in plants come from

from transposons jumping in and out

transcription

DNA to RNA

microsatellites

5 nucleotide repeats throughout genome

minisatelittes

telomeres >6 nucleotide repeats at the end of chromosomes repeated about 2500 times

telomeres

get shorter with age in animals

protects end of chromosomes

prevent chromosomes binding to eachother

main sources of extra dna in animals

retrotransposons

introns

main sources of extra dna in plants

duplications

reterotransposons

nuclear genomes

linear dna molecules

bound to chromosomal proteins (chromatin) to form chromosomes

cytoplasmic genomes

no chromosomal proteins

mitochondria

plastids

plastid

cpDNA

60-100 genes per chromosomes

many copies

mitochondrial

mtDNA

37 genes per chromosome (in human)

1 - chromatid

2- centromere

3- short arm

4- long arm

what forms from mitosis

1 diploid into 2 diploid

what forms from meiosis 1

1 diploid into 2 haploid

what forms from meiosis 2

2 haploid into 4 hapliod

chromatid

contains nuclear strand of dna (both chromatids have same dna)

homologous chromosomes

pairs of chromosomes

mitosis

prophase

metaphase

anaphase

telophase

meiosis 1 vs mitosis and meiosis 2

homologous chromosomes separated vs chromatids separated

spermatogenesis

spermatogonium undergo mitosis to primary spermatocyte undergo meiosis 1 to secondary spermatocyte undergo meiosis 2 to spermatids

oogenesis

oogonium undergo mitosis to primary oocyte undergo meiosis 1 to form secondary oocyte and primary polar body

meiosis 2 creates ovum and secondary polar body

genome

all genetic material in chromosome set

genotype

all the genes in an organism

genome size known as

C value

C value paradox

genome size in eukaryotes does not reflect the complexity of the organism

why do birds have small genomes

small cells because of high metabolic rate cause of flying

G value paradox

gene number in eukaryotes does not reflect complexity of organism

why do plants have so many genes

they need more genes - photosynthesis, natural chemicals complex defence system

genome duplication is very common in plants during evolution

polyploidy

increased number of the whole set of chromosomes

how do polyploids arise

nondisjunction

self fertilisation

polyploid animals

clawed frogs, flatworms, leeches, brine shrimp

effects of polyploidy

larger cells and organs

increased stress tolerance

buffering of deleterious mutations