Final Flashcards
chromosome
DNA molecule with many proteins in a eukaryotic cell
chromatid
when a DNA molecule duplicates itself, each duplicated segment is a sister chromatid attached at the centromere
chromosome number (basic)
sum total of chromosomes in a cell
gametes
sex cells (eggs and sperm)
human chromosome number
diploid chromosome number is 46
why is mitosis important?
so cells can reproduce and don’t die/ cos they cannot last forever
mitosis
division of diploid somatic or body cells, asexual reproduction
meiosis
division of haploid germ cells for gamete (sperm and egg) formation, sexual reproduction
cell cycle
cycle starts when a new cell forms, during cycle, cell increases in mass and duplicate its chromosomes, cycle ends when new cell divides
stages of interphase
G1: interval or gap after cell division when cell grows
S: DNA is duplicated
G2 Phase: cell prepares for cell division
Details of Mitosis
Prophase Metaphase Anaphase Telophase Cytokinesis
Prophase
cytoskeleton begins to breakup, nuclear envelope starts to break up, each pair of centriole moves toward opposite pole of cell
Metaphase
nuclear envelope completely disintegrates, microtubules attach to the 2 sister chromatids of each chromosome and start to pull, all chromosomes are lined up at equator
anaphase
sister chromatids of each chromosome are pulled apart, once separated-each chromosome moves to opposite pole.
telophase
2 nuclear membranes form, 1 around each set of chromosomes
cytokinesis
2 daughter cells, each with same chromosome number as parent cell
asexual reproduction
single parent produces offspring, all offspring are genetically identical to one another and to parent
sexual reproduction
involves meiosis, gamete production, fertilization, produces genetic variation among offspring
chromosome number (deeper definition)
sum total of chromosomes in a cell, germ cells are diploid, gametes are haploid, meiosis halves chromosome number
gamete formation
gametes are sex cells, arise form germ cells
crossing over
each chromosome becomes zippered to its homologue, all 4 chromatids are closely aligned, non-sister chromosomes exchange segments
genes
units of info about specific traits, specific segment that does for specific trait, passed from parent to offspring
alleles
different molecular forms of a gene, ex: eye color
allele combinations
homozygous: having 2 identical alleles at a locus AA
heterozygous: having 2 different alleles at a locus Aa
Genotype
refers to particular genes an individual carries
phenotype
refers to individual’s observable traits
Gregor Mendel
used pea plants to breed, found indirect but observable evidence of how parents transmit genes to offspring
phenotype ratio/ genotype ratio
phenotype: pink, white
genotype: 2 Aa, aa
Mendel’s Theory of Segregation
an individual inherits a unit of info (allele) about a trait from each parent, during gamete formation (meiosis) the alleles segregate from each other
Dihybrid cross
experimental cross between individuals that are homozygous for different versions of 2 traits
Mendel’s Theory of Independent Assortment
Mendel concluded that the 2 units for 1st trait were to be assorted into gametes independently of the 2 units for other trait, members of each pair of homologous chromosomes are sorted into gametes at random during meiosis
karyotyping
take chromosomes and pair them based on size
galactosemia
newborn babies unable to digest milk
progeria
rapid aging due to mutated gene
nondisjunction
where mistakes happen
aneuploidy
individuals have 1 extra or less chromosome, major cause of miscarriages
polyploidy
individuals have 3 or more of each type of chromosome
amniocentisis
analyze how many chromosomes the child will have by getting sample from pregnant mom (determine sex)
Nucleotides
- 5-carbon sugar-either ribose or deoxyribose
- phosphate group
- nitrogen-containing base
How do proteins form?
requires 3 types of RNA molecules and 2 processes
transcription
part of 1 DNA strand unwinds and used as template, enzyme RNA polymerase adds free nucleotides using DNA as a template, single strand of RNA-transcript- is formed
translation
messenger RNA (mRNA) with DNA protein building info leaves nucleus and goes to ribosome in cytoplasm, ribosomal RNA (rRNA) translates the info to make polypeptide chains
transgenic
take genes from other plants and put into new organism
Human genome project
private companies announced they would sequence and patent human genome,
President Clinton and Tony Blair announced that human genome could not be patented.
genomics
study of genomes
structural genomics: determines 3-dimensional structure of proteins encoded by genome
comparative genomics: compares genomes of different species to determine evolutionary relations comparing similarities and differences
mouse and humans: 78% identical
banana and humans: 50% identical
Genetic engineering
lab process by which deliberate changes are introduced into an individual’s genome
ex: bacteria used in producing a) human insulin b) digesting toxic wastes
