Multicellular Organisms Part II Flashcards
What is continuous variation
Continuous variation describes a characteristic of an animal or plant that shows a range of values between a minimum and maximum value
What are the examples of continuous variation
Height Leaf length Tail length in mice Hand span Shell diameter
What is discrete variation
Discrete variation describes a characteristic that can be separated into distinct categories.
What are the examples of discrete variation
Finger print Earlobe shape Tongue rolling ability Blood group Eye colour
What is an allele ?
Alleles are different forms of genes.
Finish this sentence
During gamete formation the chromosomes are reduced to a …
Single set
What is a genotype
The set of genes possessed by an organism (always written in letters)
What is dominant ?
The version of a gene that always makes the presence of a recessive allele
What is recessive
The version of a gene that always masked by the dominant allele. Requires two recessive alleles for phenotype to be expressed
What does homozygous mean
A genotype that contains two identical alleles for a particular gene.
What does heterozygous mean
A genotype that contains two different alleles for a particular gene
What does true breeding mean
When both parents have homozygous genotypes.
What does polygenic inheritance mean
When a characteristic controlled by the alleles of more than one gene
What does phenotype mean
The appearance of the physical characteristic (e.g. Blue eyes)
What is a xylem
It is a dead cell in plants. It is a hallow tube with rings of lignin. It transports of water and minerals from the soil. Also provides support.
What is a phloem
It transports sugar in all directions in plants. It is a living cell.
What do sieves plates do
They are end walls with pores, which allows rapid transport of sugar.
What do cytoplasm strands do
They help move sugar from one sieve tube to another
What is a cuticle, what is its feature and function
Cuticle - waxy layer, protects and waterproofs
Epidermis, what is its feature and function
Epidermis - close fitting cells, it protects
Mesophyll, what is its feature and function
Mesophyll - contain many chloroplasts, major site of photosynthesis.
Vein, what is its feature and function
Tubes made of xylem & phloem, transport water & sugar
Guard cell, what is its feature and function
Changes shape, open and close stomata pores.
Stomata, what is its feature and function
Found in the leaf, pore, allows evaporation of water and gas exchange
Explain the leaf structure
In leaves, water molecules move from the xylem vessels, in the leaf vein, into the surrounding cells. They move through the spongy Mesophyll layer by osmosis down a concentration gradient.
Why do plants need minerals
Plants use minerals from the soil to build the complex molecules they need to survive and grow. Poor plant growth may be due to a deficiency of one or more minerals
What is osmosis
It is the diffusion of water from a high water concentration to a low water concentration to a selectively permeable membrane. Water enters root hair cells by osmosis.
What is required for a healthy growth and development
A balanced diet
Suitable growing conditions
Water
Vitamins and minerals
What is transpiration
How water is lost through the stomata in the leaf
Why do plants need transportation in plants
Plants need transport systems in order to move water and dissolves flood from one part of the plant to another.
What does a balanced diet contain
A balanced diet contains a mixture of foods from all the Amis food groups
Why are vitamins and minerals needed.
Vitamins and minerals are needed to keep the body healthy
Why do we need suitable growing conditions
Animals require the correct environment, shelter and care in order to grow and develop healthy
What is water considered to be
Water is considered to be the most important nutrient fro healthy growth and development.
What are the two types of variation
Continuous variation
Discrete variation
