Multicellular Organisms Flashcards
What are hormones?
They are chemical messengers
What releases hormones into the bloodstream?
The endocrine glands
What is glucagon and what does it do?
Glucagon is a hormone produced by the pancreas which triggers glucose conversion into glycogen
What is glycogen?
Glycogen is stored carbohydrates
What is the pancreas?
The pancreas is the organ that produces digestive enzymes and the hormones glucagon and insulin
What is the liver?
The liver is the large organ involved in blood glucose conversion
What does the cerebellum control?
It controls coordination, movement and balance
What does the cerebrum control?
It controls memory conscious thought, intelligence and emotions
What does the medulla control?
It controls breathing and heart rate
What are the structures in the brain?
The cerebellum, medulla and cerebrum
What is the nervous system?
It is a communication system that uses electrical impulses tp send messages from one part of the body to another
CNS= Brain + spinal cord
What is a motor neuron?
Nerve cells that carry electrical impulses from the CNS to muscles and glands. This can be a rapid or slow response
What is an inter neuron?
Nerve cells that are found in the CNS where they connect with other neurons
What is a sensory neuron?
Nerve cells that carry electrical impulses from sense organs to the CNS
What is a chromosome compliment?
The number of chromosomes found in a cell
What is a chromosome?
Chromosomes are thread like structures found inside the nucleus.
They carry genetic information
What part of the cell controls mitosis?
The nucleus
What is mitosis?
Mitosis is the process of cell division where the nucleus is duplicated.
What is a chromatid?
It is a replicated copy of a chromosome
What are stem cells and what do they divide to produce?
Stem cells are unspecialised cells
they divide to produce either more stem cells or cells that develop into specialised cells
What is the sequence of events in mitosis?
Start with chromosomes replicating to become visible pairs of chromatids.
Chromosomes line up along the equator and get pulled apart by spindle fibres.
2 Nuclei form.
Cell cytoplasm’s separate and 2 identical daughter cells are formed.
What is haploid?
Haploid means the cell contains only 1 set of chromosomes
Are gametes haploid or diploid?
Gametes are haploid
What is an allele?
The form of a gene.
Different alleles will result in variation of characteristics
What is a gene?
A gene is the basic unit of inheritance and many genes together make up a chromosome.
Each gene controls an inherited characteristic.
What is continuous variation?
Continuous variation is the polygenic inheritance of characteristics where there is a range of values from one extreme to another.
(eg. height)
What is discrete variation?
Discrete variation is the dingle gene inheritance of characteristics where measurements fall into distinct groups.
(eg. blood types)
What is fertilisation?
Fertilisation is the fusion of the nuclei of the 2 haploid gametes to produce a diploid zygote, which divides to form an embryo.
What organ produces the female gamete in animals?
The ovaries
they produce the female gamete ova (egg)
What organ produces the male gamete in animals?
The testes
testes produce the male gamete sperm
What organ produces the female gamete in a plant?
The ovaries
Ovaries contain ovules which contain the female gamete.
What organ produces the male gamete in a plant?
The anther
It produces pollen grains that contain the male gamete.
What is a zygote?
Zygotes are produced when 2 haploid cells fuse together to produce a diploid cell.
What is a gamete?
Gametes are sex cells and can either be male or female.
What is diploid?
Diploid means the cell contains 2 sets of chromosomes.
What is transported in xylem vessels?
Water and dissolved minerals
What is transported in phloem?
Sugar/food
What is xylem made from and is it dead or alive?
Xylem are tubes of hollow dead cells
They are strengthened by rings of lignin.
What are plant organs?
Plant organs are roots, stems and leaves
What are the 7 parts of a leaf?
Palisade mesophyll, Upper epidermis, Spongy mesophyll, vein (consisting of phloem and xylem), Guard cells. Stomata, Lower epidermis
How do water and minerals move into the plant?
It enters through root hairs via osmosis and are the transported in xylem vessels.
Why do xylem cells have rings of lignin?
To support the cell and withstand changes of pressure as water moves through the plant.
What is transpiration?
Transpiration is the process of water moving through a plant and its evaporation through the stomata
What factors affect rate of transpiration and do they increase or decrease it?
Increased Wind Speed = Increase
Increased Humidity = Decrease
Increased Temperature = Increase
Increased Surface Area = Increase
What is the function of a guard cell?
It controls the opening and closing of stoma and when closed it can prevent water loss
What is the function of the upper epidermis?
This is a single layer of cells containing few or no chloroplasts.
The cells are fairly transparent and allow most of the light to pass through to the cells below them.
What is the function of the lower epidermis?
The lower epidermis contains stomata cells that help control water loss and help regulate gas exchange.
