Egg to organism Flashcards
Features of an egg
half of nuclear dna
cytoplasm
- organelles
- nutrients
- mRNA ans proteins
Features of sperm
Half of nuclear DNA
- centriole
cleavage in mammals
slow, asynchronous and rotational
= results in blastocyst
The blastocyst 5-6 days after fertilisation
- inner cell mass forms embryo
- Trophoblast contributes to placenta and umbilical cord
- Blastocyst cavity contains factors for cellular differentiation
The blastocyst 5-6 days after fertilisation
- inner cell mass forms embryo
- Trophoblast contributes to placenta and umbilical cord
- Blastocyst cavity contains factors for cellular differentiation
Gastrulation
formation of tissue layers
Germ layers
Ectoderm, Mesoderm, Endoderm
What will ectoderm form
epidermal layer of skin
what will endoderm form
lining of the gut, liver and lungs
what will mesoderm form
muscle, bone, kidneys, blood, gonads and connective tissues
epiboly
flattening and extension of cells that occur on the outside of the blastula
convergent extension
intercalation of cells in the direction of movement that drives involution
How is gastrulation initiated
fertilisation triggers the rotation of the cortical cytoplasm that leads to formation of the grey crescent
Neurulation
formation of organs and their systems
what happens during neurulation
the ectoderm caves in and folds over to create the neural tube
What are somites
segments of mesodermal tissue that form along the length of the neural tube
formation of the somites induces…
body segmentation
How genes
group of related genes that control the body plan of an embryo along their anterior - posterior axis
Three permanent layers of plant development
dermal, ground and vascular
Two meristems
regions containing undifferentiated cells that will continue to give rise to new tissues and orchestrate growth
Dermal tissue
covers and protects the plant, and controls gas exchange and water absorption
Ground tissue
- structural support
- carries out photosynthesis
- stores water and nutrients
Vascular tissue
- transports water, minerals and sugars to different parts of the plant
How does tissue morphology arise in plants
from the regulation of cell division and cell elongation
Shaping plant tissue
plant cells do not use cell migration to organise tissues due to their rigid cell walls
