OCR Biology A - 2.1.6 - Cell Division, Cell Diversity and Cellular Organisation Part 4

Can become any type of cell within a group of cells e.g. any type of blood cell

Embryonic stem cells Umbilical cord blood Adult stem cells found in bone marrow of flat bones, skin, adipose tissue, brain, blood iPS (induced pluripotent stem cells)

Developed in lab by reprogramming differentiated cell’s to switch on genes and become pluripotent

Bone marrow transplants (used to treat sickle-cell anaemia and leukaemia) Drug research (check toxicity) Test effectiveness of medicines Study cell function to find out what can make it fail Developmental research - studying cells to see how they develop into diff cell types

Erythrocytes | Neutrophils

Having only one set of chromosomes

Matching chromosomes, containing the same genes at the same places (loci) May contain different alleles for some of the genes

Having two complete sets of chromosomes (found as pairs)

These chromosomes will have the same genes as the maternal homologue in the chromosome pair

These chromosomes will have the same genes as the paternal homologue in the chromosome pair

Replicated of chromosomes, originating from different chromosomes

Long and cylindrical - able to pack several together Chloroplasts - absorb as much light as possible Large vacuole - stores nutrients/water, provides structural support, stores waste Cytoskeleton / motor proteins - moves chloroplasts to reduce CO2 diffusion pathway

Mitochondria - releases energy for movement Acrosome - digestive enzymes (egg) Protein fibres in flagellum - enable rapid movement/ strength Nucleus - contains genetic info (haploid gamete)

Thicker inner wall - so cell doesn’t change symmetrically when turgid Large vacuole - to take up water and expand stoma Active pump - move water in/out to alter water potential of cell Stomata - O2 and CO2 can diffuse out

Cilia - move mucus | Goblet cells - produce mucus and trap harmful substances

Flat - cover a large area | Thin - short diffusion pathway

Membrane bound receptors - recognise materials that needs to be destroyed Well developed cytoskeleton - enable movement Many mitochondria - release energy needed Multi lobed nucleus - easy to squeeze through small gaps Granular cytoplasm - contains lysosomes w/ digestive enzymes to attack pathogens

No nucleus - more space for haemoglobin Small and flexible - fit through capillaries Flattened bioconcave shape - increase SA:V - take in more O2 Well developed cytoskeleton - allows it to change shape

Long extension - increase surface area for diffusion Active pump - absorb mineral ions and water through active transport Thin cell wall - short diffusion pathway Vacuole containing sap - low water potential (sugars and ions) - water can diffuse in

By numerous plasmodesmata

Connections between cells where the cytoplasm is continuous

Chromosomes that contain same alleles Same length Centromeres in same position

Pair of homologous chromosomes

Checks cell is ready for S phase

Checks DNA has replicated correctly

No

Where each chromatid touches (usually in the middle)

The separating chromatids of a pair aren’t the same

Stem cells in bone marrow

Proteins

Prophase I

It provides opportunities for new genotypes to arise

A region of repetitive nucleotide sequences at the end of a chromatid

Haemoglobin is synthesised | Organelles associated w/ protein synthesis are digested

Embryonic cells in blastocyst

Stem cells of fertilised eggs

Skip from Anaphase 1 to Prophase 2

Group of cells that can contract together