BIO TEST Flashcards
(34 cards)
What is a gene and what does it code for?
A gene is a segment of DNA that codes for a specific protein
What are the steps of gene expression?
- Transcription (DNA to mRNA) 2. Translation (mRNA to protein)
What molecules make up DNA?
Nucleotides, consisting of a sugar, phosphate, and nitrogenous base.
What is the relationship between DNA, amino acids, and proteins?
DNA sequences determine amino acid sequences, which fold into proteins.
What is the role of mRNA in protein synthesis?
mRNA carries genetic information from DNA to ribosomes for protein production.
What is cell specialisation?
The process where stem cells differentiate to form specific cell types.
What are stem cells, and why are they important?
Undifferentiated cells that can develop into different cell types.
What are examples of specialised cells in the human body?
Neurons (nerve cells), erythrocytes (red blood cells), muscle cells.
What are the 4 nitrogenous bases in DNA?
adenine (A), thymine (T), guanine (G), and cytosine (C).
Where does gas exchange occur in plants?
Stomata, spongy mesophyll, epidermal cells.
What is the technical name for water loss in plants?
Transpiration.
What is the worded equation for photosynthesis?
Carbon dioxide + water → glucose + oxygen.
What factors affect the rate of gas exchange in plants?
Light intensity, temperature, humidity, wind speed.
What are stomata, and how do they operate?
Stomata are pores in leaves that open/close via guard cells turgidity.
How do guard cells regulate gas exchange?
They open and close stomata by changing turgor pressure.
What are the four main characteristics of exchange surfaces?
- Large surface area 2. Thin barrier 3. Moist surface 4. High concentration gradient.
What are the types of transport across membranes?
Simple diffusion, facilitated diffusion, active transport.
Which transport methods require energy?
Active transport (moves substances against the concentration gradient).
What is osmosis, and how does it work?
The diffusion of water across a selectively permeable membrane.
How do blood capillaries facilitate exchange?
Thin walls allow diffusion of oxygen, nutrients, and waste.
What is the functional unit of the lung?
Alveolus.
What gases are exchanged in the alveoli?
Oxygen (O2) in, Carbon dioxide (CO2) out.
How do alveoli maximize gas exchange?
Large surface area, thin walls, moist lining, and rich blood supply.
How does smoking affect the respiratory system?
It damages cilia, increases mucus, and reduces gas exchange efficiency.
