Unit 1 - Cell biology Flashcards
What is the type of cell division that makes animals and plants grow called?
Mitosis
What can mitosis replace?
Old and damaged cells
What is the process of Mitosis?
1) Chromosomes replicate becoming pairs of chromatids.
2) Chromosomes start to become visible
3) Spindle fibres form and chromosomes move to the equator of the cell
4) Chromatids are pulled to opposite ends of the cell
5) The nuclear membrane forms
6) The cytoplasm divides and two daughter cells are formed
What is a tissue?
A group of the same cells working together specialised to do a job
What is an organ?
A group of the same tissues working together specialised to do a job
What is an organ/body system?
When 2 or more organs are working together
What are types of organ systems?
Digestive, Nervous Circulatory, Respiratory, reproductive.
What makes up the central nervous system?
Brain and spine
What are the three main types of neurons?
Sensory, Inter and Motor
What doe the sensory neuron do?
Takes stimuli info from the receptors to the CNS
What doe the Inter neuron do?
Operate within the CNS, which processes info from the senses that require a response
What does the Motor neuron do?
Enables a response to occur at an effector
What is the order in the reflex arc?
Stimulus -> Receptors/Sense organ e.g. eyes, ears, skin -> Sensory Neuron -> Inter Neuron -> Motor Neuron -> Effector e.g. muscle and glands -> Response
What are synapse and what do they do?
A synapse is a gap between neurons. Chemical transmitter substances called neurotransmitters are release from tiny sacs at the end of the neuron across the synapse to make an electrical impulse in the next neuron which carries the message along the neurons. (They carry chemical messages between neurons)
What does the cerebrum control?
Learning, memory, imagination, consciousness, thoughts and intelligence.
What does the cerebellum control?
Balance and muscle coordination.
What does the medulla control?
Breathing rate, heart beat and peristalsis.
What happens if the blood glucose concentration in the blood is too low?
Cells cannot no make ATP for energy.
Why are only some tissues affected by a hormone (chemical) message?
A target tissue has cells with complementary receptor
proteins for specific hormones, so only the tissue which is specific to that hormone will be affected.
What is the function of the Petals?
Attract insects
What is the function of the Anther?
Makes pollen
What is the function of the Stigma?
Catches pollen grains
What is the function of the Style?
Pollen tube grows down through this
What is the function of the Ovary?
Contains ovules
What is the function of the Ovule?
Turns into seeds when they fuse with pollen
What is the function of the nectarry?
Produces nectar (sugar) to attract insects
What is continuous characteristics controlled by?
Many genes which is also called polygenic inheritance
What is discrete characteristics controlled by?
one single gene
What are different forms of genes called?
alleles
What is the phenotype?
The physical characteristic which is shown?
What is the genotype?
The alleles an organism has/carries for a particular characteristic
What are examples of homozygous alleles of a gene?
BB/bb
What are examples of hetrozygous alleles of a gene?
Bb
What does the xylem transport and what are it’s properties/structure?
Water and minerals, is a non-living tissue that has lignin to provide strength. Xylem cells are lignified to withstand the pressure changes as water moves through the plant.
What does the phloem transport and what are it’s properties/structure?
Vessels transport sugars made in photosynthesis all around the plant. Phloem tissue is made of 2 types of living cell:
- Sieve tubes - have continuous cytoplasm with neighbouring cells with an end plate like a sieve
- Companion cells - have a nucleus to control sieve tube cells
What does a plant have to be able to transport to survive
- Water from roots
- Glucose from photosynthesis
- Minerals from soil