Cells and Control Flashcards
What is a gene?
a section of DNA which determines a characteristic and codes for a protein.
What are Chromosomes?
tightly coiled lengths of DNA containing many genes.
How many pairs of chromosomes do humans have?
23 pairs
When do Cells divide?
an organism grows
an organism becomes damaged and needs to produce new cells for repair
organisms like bacteria reproduce asexually
What is the cell cycle?
A growing and dividing cell goes through a series of stages.
What is the Cell Cycles first stage?
cell growth and then synthesis of DNA
What is mitosis?
A type of cell division which produces daughter cells identical to the parent.
What happens in the Interphase?
The DNA in chromosomes copies itself ready for mitosis.
What happens in the prophase?
chromosomes and their copies condenses to become more visible. The membrane around the nucleus disappears.
What happens in the metaphase?
Chromosomes and their copies line up in the middle of the cell.
What happens in the Anaphase?
Chromosomes and their copies are pulled to different ends of the cell.
What happens in the telophase?
New membranes form around the chromosomes at each end of the cell.
What happens in the cytokines?
The cell membrane pinches in and eventually divides into two daughter cells.
What are the stages of mitosis?
prophase, metaphase, anaphase and telophase.
What happens when a cell becomes cancerous?
begins to grow and divide uncontrollably.
What do a group of cancerous cells produce?
a tumour
What are the two types of tumours?
Benign and Malignant
What are the two main types of animal stem cells?
Embryonic
Adult
What passes along nerve cells?
Electric impulses
Where in the body does mitosis take place
Everywhere
What are 2 uses of plant stem cells?
They can be used to produce clones of whole plants
They can be used to grow more rare plant species
What are the steps of mitosis and cytokinesis?
DNA condense to form chromosomes
Chromosomes line up in the centre
Cell fibres separate two arms of chromosomes to opposite side of cell
Cytokinesis - the entire cell divides to form two identical daughter cells
What do we call plant tissues that are continually growing?
Meristem tissue
Why are reflexes so fast?
they are automatic that don’t require the brain
How does a synapses transmit an electrical signal?
releases of chemicals
What do we call cells produced by mitosis?
Daughter cells
What is the role of a sperm cell?
to deliver genetic material to an egg cell and fertilise it
When does cellular differentiation mostly occur?
during the development of the embryo and foetus
What type of cells make up the nervous system?
Nerve cells
What is the role of the motor neurone?
Transfers a signal from CNS to and effector
What does differentiation mean?
cells become specialised
How many pairs of chromosomes do human cells usually have?
23
What is the central nervous system composed of?
Brain and spinal cord
How many did ions are there when a cell divides by mitosis?
1 division
What is the role of a receptor?
To detect the stimulus
What are the two main features of stem cells?
They can divide by mitosis
They can differentiate into different types of specialised cells
What are 3 reasons multicellular organisms need new cells?
Growth
Development
Repair
Are cells produced by mitosis identical or unique?
identical
What is the role of a sensory neurone?
Transport a signal to the CNS
What is the cell cycle?
the series of steps that take place as a cell grows
What is a stem cell?
an undifferentiated cell
What is the gap between never cells called?
a synapse
What are 2 main types of effectors?
Muscles
Glands
What is a specialised cell?
a cell that is adapted to perform a particular function
Where are embryonic cells found?
in the embryo
Where are adult stem cells found in the body?
in bone marrow
What is the role of a relay neurone
To transfer from a sensory neurone to a motor neurone
What are 3 diseases that can the treated with stem cells?
Anaemia
Paralysis
Type 1 diabetes
