D2.1 - cells and nuclear division Flashcards
microtubules
long, thin fibrous proteins that forms the spindle
microtubule motors
binds to microtubules & hydrolyses ATP to produce energy to move chromosomes during cell division
Budding
asexual reproduction in yeast
- outgrowth of genetically identical daughter cell (bud from parent cell)
hydra
genus of small aquatic invertebrates that bud
- rapid increase in population
budding scar
determines how old & how many times the cell has divided
prokaryotic vs eukaryotic division
prokaryotic: divides by binary fission
eukaryotic: mitosis or meiosis (to create gametes)
homozygous
two of the same allele
heterozygous
two different alleles
mitosis
Mitosis is a type of nuclear division that produces two genetically identical diploid daughter nuclei for somatic cells
chromosome
wo genetically identical sister chromatids held together at the centromere.
microtubule organising centres (MTOCs)
Structures within cells that regulate the formation and organisation of spindle fibres. (PLANT CELL)
centrosomes
a type of MTOC that contains centrioles. MTOCs migrate to each pole (end) of the cell during prophase.
(ANIMAL CELLS)
meiosis
type of nuclear division that produces four haploid genetically unique daughter nuclei, which will form gametes for sexual reproduction
bivalent/ tetrad
A pair of homologous chromosomes that come together during prophase I of meiosis.
homologous pair
Paired chromosomes that have the same genes at the same locations.
allele
a variant/ version of a gene
Karyotyping
Determining or analysing the karyotype (number, size and shape of the chromosomes) of an individual.
chiasmata
points at which crossing over occurs between two non-sister chromatids
non-recombinant chromatids
Chromatids that have not undergone crossing over.
meristem
Regions of undifferentiated cells at the tips of roots and shoots, in plants, that have the potential to become any cell type in the plant.
mutation
changes in DNA sequence
cyclins
family of proteins that regulate the cell cycle.
- binds to and activates CDK enzymes that phosphorylate specific proteins.
mutation
- change in sequence of genetic material
hermaphroditic
An organism with both male and female reproductive organs
ex. pea plant
true breeding parents
An organism that always passes on its phenotypic traits to the offspring.
genes
segment of DNA that codes for specific protein
genotype
- different combinations of alleles
phenotype
- physical traits
- outward expression of allele combos with environmental factors
SNP
single nucleotide polymorphism
- most common variants in humans
- at single nucleotide/base pair when genome is copied
- can be in a gene that codes for a protein or in parts of the DNA for other functions
explain blood type and multiple alleles
- A, B and O allelic forms
- chromosome 9
- ABO gene
- each make their own enzyme that catalyze specific sugars on the outside of the cell
- sugars produce immune response - antigens
codominant
2 alleles are both expressed equally - AB blood type
incomplete dominance
A third phenotype that is intermediate between the dominant and recessive can be produced.
linked vs unlinked
linked - Genes on the same chromosome that are usually inherited together
unlinked - genes on different chromosomes
mitotic index
proportion of actively diving cells
tumor suppressor genes and protooncogenes in mutations
tumor suppressor genes: code proteins that suppress cell growth
protooncogenes: code proteins to promote cell growth
mutations in those genes cause uncontrolled division
Outline the process of cytokinesis in plant and animal cells.
animal cells:
actin and myosin proteins form contractile ring
pinches cell membrane together (fluidity helps)
forms cleavage furrow
plant cells:
cell plate, formed when vesicles (that contain materials) fuse in the middle
forms new cell wall
aneuploidy and polyploidy
don’t add to 46. extra or missing chromosome(s)
law of segregation
gametes only carry one allele for a gene
