B1 and B2 in general Flashcards
What cell differentiation
Is process in the cell changes to become a specialised for job
4 types of specialised cells
Sperm cells - long tail, streamlined cell, mitocondria
Root hair cell - long hairs that stick out, large SA
Nerve cell -
Phloem and xylem - transports food and water joined end to end
Explain Growth and DNA replication
Dna spreads out in long strings
The cell grows in size, making more sub-cellular structure
Duplicates DNA, only one copy of new cell
Explain mitosis
Chromosomes lines lines up in centre
Cell fibres pull then apart to opposite sides
Membranes forms around the chromosomes, nuclei forms
Cytoplasm and cell membranes divide
Explain binary fisson
DNA replicates
Cell gets bigger and the DNA moves to opposite strands of the pole
Cytoplasm divides
Explain active transport in root hair cells
Allows plant to absorb minerals from a dilute solution across a concentration gradient.
Root hairs cells are covered with hairs.
Gives plant large SA for absorbing water/ mineral ions
Concentration is always higher in root hair cells
Plants use ATP energy for active transporta
How is the leafs structure adapted for gaseous exchange
Leaf covered with stomata at the bottom
Size of stomata are controlled by guard cells
Flat shape of the leaf
How does gills provide good gaseous exchange
Gills are made up of filaments, gives large SA
Filaments covered with lamellae, increases SA even more
Lamellae surrounded by capillaries.
Thin layer of cell
Water and blood flows in opposite directions maintaining a concentration gradient
Explain the iodine test
Starch
5cm3
Brown to black
Explain biuret test
Proteins
2cm3
Blue to pink
Sudan III
Lipids
5cm3
Red separation to the top
Benedict solution
Sugars
5cm3
Water bath at 75
Blue to green, yellow or red (how much sugar)
What type of membrane surrounds the lungs
Pleural
4 things that affect Transpiration
Light - higher light intensity cause more stomata to open up and more co2 and o2 to diffuse.
Temperature - warmer mean faster rate because particles are supplied with more kinetic energy
Air flow - strong wind increases the rate because maintains a higher concentration of particles inside the leaf. Diffusion can occur
Humidity - low humidity means more transpiration because less water particles outside of the leaf
List 4 lifestyle choice that causes cancer
Smoking
Obesity
UV radiation
Viral infection
Explain upper epidermis
Transparent
Light can pass through
Explain palisade layer
Has lots of chloroplast
Near top of the leaf, receive more light for photosynthesis
Explain the role of xylem and phloem
Network of vascular bundles
Deliver water and nutrients
Take away glucose
Support to structure
How is the lower epidermis adapted for gas exchange
Full of stomata
The shape of stomata controlled by guard cells
How does spongy mesophyll layer help diffusion
Has many air spaces
Explain what a meristem is
Found at growing tips of a shoot or roots. They can differentiate into other types of cells, making plant to grow
Describe structure of phloem
Made from elongated living cells with small pores at the walls, cell sap flows through it
Companion cells packed with mitochondria
What does phloem tubes transport
Food substances, dissolved sugars
For immediate uses of storage
Xylem structure…Explain
Made up of dead cells joined together
Has no end walls
Hollow
Strengthened by lignin
What does xylem transport
Water and mineral ions
Fromm roots to the stem and leaves
