Biology Flashcards
What are the basic units of life?
Cells
Living organisms are made up of cells, which can be unicellular or multicellular.
What is the main function of the cell membrane?
Controls what leaves and enters the cell
It is selectively permeable.
What does the nucleus control?
All the cells’ activities
It contains DNA in the form of chromosomes.
Where does aerobic respiration take place in animal cells?
Mitochondria
What is the function of ribosomes?
Where proteins are made
What is the role of chloroplasts in plant cells?
Site of photosynthesis
Contains chlorophyll which traps light energy.
What maintains the shape and provides support in plant cells?
Cell wall
What do vacuoles in plant cells contain?
Cell sap
What is meant by ‘specialised cells’?
Cells adapted to perform a particular function
What is the purpose of staining when observing cells under a microscope?
To help visualise structures
How is magnification calculated?
Using a specific equation involving the size of the image and the actual size of the object
What is DNA?
Deoxyribonucleic acid, organised into chromosomes
What is the shape of DNA?
Double helix
What are the four bases in DNA?
- A (adenine)
- T (thymine)
- C (cytosine)
- G (guanine)
What is complementary base pairing?
A pairs with T and C pairs with G
What are genes?
Sections of DNA on chromosomes that contain instructions for making proteins
What is the process of cell division called?
Mitosis
What happens during the replication stage of cell division?
DNA is replicated
What can mutations in genes cause?
Cancer
What are some agents that can cause mutations?
- Radiation (UV, X-rays)
- Certain chemicals
- Smoking cigarettes
What is gene therapy?
A treatment that involves adding genes to bone marrow cells
What is the role of viruses in gene therapy?
To carry healthy genes into affected cells
What are stem cells?
Unspecialised cells that can replicate and become specialised
What are the two types of stem cells?
- Embryonic stem cells
- Adult (tissue) stem cells
What is binary fission?
The process by which bacteria reproduce rapidly
What is the structure of bacterial DNA called?
Chromosomal DNA
What does aseptic technique refer to?
Practices to prevent contamination from microbes
What is yeast?
A type of fungus that is single-celled
What is the process by which yeast reproduces?
Budding
What is respiration?
The process by which cells gain energy
What is the equation for aerobic respiration?
Sugar + Oxygen 🡪 Water + Carbon dioxide + Energy
What occurs in the absence of oxygen during respiration?
Fermentation
What is the optimum temperature for enzyme action in the human body?
37°C
What happens to enzymes beyond their optimum temperature?
They denature and lose function
What is amylase?
An enzyme that breaks down starch into maltose
What is the function of the stomach in digestion?
Produces acid and digestive enzymes
What is the role of the pancreas in digestion?
Produces enzymes to aid digestion
How can the presence of starch be tested?
Using iodine
What color change indicates the presence of sugar when using Benedict’s reagent?
Changes from pale blue to red/orange
