biology stuff Flashcards
List 5 structures in plant cells
Cell membrane, cell wall, cytoplasm, vacuole, nucleus
What is the epidermis in plants
Epidermis, in botany, outermost, protoderm-derived layer of cells covering the stem, root, leaf, flower, fruit, and seed parts of a plant. The epidermis and its waxy cuticle provide a protective barrier against mechanical injury, water loss, and infection.`
Explain why it is important to the plant that the tissue is transparent.
It allows light through, traps energy from light, needs light for photosynthesis, light reaches chloroplasts
Describe the function of stomata
For gas exchange, photosynthesis, controls rate of diffusion/transpiration
Describe how the ions move into the guard cells
Move against the concentration gradient using energy from respiration
Describe and explain how the change in ion concentration causes the guard cell volume to change.
higher ion concentration results in larger guard cell volume, causes lower water potential, causes water to move into guard cells across partially permeable membrane by osmosis
Suggest two environmental factors that can cause plants to wilt
Lack of water
high temperature
What are the two types of variation
There are two kinds of variation: continuous and discontinuous
What is Continuous Variation
Continuous Variation is when there are very many small degrees of difference for a particular characteristic between individuals and they are arranged in order and can usually be measured on a scale. Examples include height, mass, finger length
What is discontinuous variation
seen where there are obvious, distinct categories for a feature. - no intermediates between categories, the feature cannot usually change during life. - caused by a single gene/a small number of genes, with no environmental influence.
Describe how a blood clot forms
fibrinogen is converted to fibrin
Fibrinogen is soluble, fibrin is insoluble
Fibrin forms a mesh
Fibrin traps blood cells
State the importance of blood clotting.
Prevents blood loss
Prevents pathogens entering wound (viruses, bacteria, fungi, protozoa, and worms.)
define the term phenotype
the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.
state the two possible genotype for a person who has the phenotype blood group A
AA
AO
Explain the role of plant hormones in gravitropism
Auxin is a plant hormone
Auxin diffuses through the plant
Auxin stimulates cell elongation
Auxin is unequal distributed, more auxin accumulates lower parts
Explain how gravitropism enables a plant to survive
Roots growing down anchor the plant
plants growing up more likely to reach light
Describe how reflexes in animals differ from sensitivity in plants
Reflexes respond faster and are not a growth response
Define the term sense organ
groups of receptor cells responding to specific stimuli
state the names of two cell structures that are involved in making or secreting proteins
Ribosomes
mitochondria
state the substance that goblet cells secrete
Mucus
Describe the process of emulsification of fats.
Mix with bile
breaks up of large fat globules into smaller fat globules
Increases surface area of fat globules
Water enables dispersion of smaller fat globules
State the name of the organ in the alimentary canal where fats are emulsified
Small intestine