Biology Flashcards
(49 cards)
Define an ecosystem.
A community and environment interacting
What molecule is the storage carbohydrate in plants humans and fungi
Plants - starch
Humans + Fungi - glycogen
How do the structures of the lungs enable a person to breathe in?
- The diaphragm contracts
- Intercostal muscles contract and pull the ribs out
- So volume increases + pressure decreases
- And air flows into the lungs
Why does height not always correlate to parents?
- Height is polygenic
- Height depends on the combination of many genes
- Heigh depends on sex
- Height may have environmental factors
What must you comment on when there are discuss questions?
Control data e.g. if they mention age and sex etc…
Describe the role of phagocytes in the body.
They engulf and digest bacteria using enzymes.
What does polygenic mean?
A characteristic or trait that is influenced by multiple genes, rather than a single gene
Describe the structure of fungi.
Body is organised into a mycelium from thread-like structures called hyphae which contain many nuclei
How do fungi eat?
Saprotrophic nutrition - secrets enzymes onto food material and absorb the organic products
What are examples of the 5 kingdoms?
Animal - Human
Plant - Onion
Fungi - Yeast
Protoctist - Amoeba
Bacteria - Lactobaciullus
What organelles do bacteria have?
Cell wall
Cell membrane
Cytoplasm
Plasmids
What is a pathogen and an example?
A disease causing microorganism - Influenza
Describe the structure of a virus.
Protein husk
Contains nucleic acid
What are the differences between prokaryotes and eukaryotes?
Eukaryotes are made up of cells that contain a nucleus with a distinct membrane whereas prokaryotes don’t have a nucleus
Give 4 different types of pathogens.
- Bacteria
- Viruses
- Protoctist
- Fungi
What is assimilation?
Small food molecules are used to build large molecules
Describe what happens in the intestines.
Small:
Duodenum - Digestion is completed by enzymes secreted by the pancreas
Ileum - Water and food molecule absorption in villi
Large:
Colon - Remaining water is absorbed, producing faeces
Rectum - Where faeces are stored
Describe what happens in the stomach.
Food is mechanically digested by churning actions whilst protease digests protein. pH is optimum for enzymes and it kills bacteria
What is gas exchange?
The process where organisms absorb oxygen and release carbon dioxide.
What are the harmful chemicals in cigarettes and what effect do they have on the body?
Nicotine:
- Narrows blood vessels and increases heart rate, leading to increased blood pressure which leads to blood clots forming in the arteries, potentially resulting in a heart attack
Carbon Monoxide:
- Irreversibly binds to haemoglobin, reducing capacity of blood to carry oxygen which puts more strain on the breathing system as frequency and depth needs to increase to supply same O₂
- It also means that circulatory systems needs to pump blood faster, raising blood pressure and increasing risk of coronary heart disease
Tar:
- Carcinogen linked to increase chances of cancerous cells developing in cells
- It also contributes to COPD which occurs when chronic bronchitis and emphysema occur together
What effect does chronic bronchitis and emphysema have on the body?
Chronic Bronchitis:
- Tar stimulates mucus glands to enlarge and produce more mucus which builds up, blocking the smallest bronchioles and leads to infections
Emphysema:
- It is a caused by a build up of infection, as phagocytes that enter the lungs release elastase - the alveoli become less elastic so many burst, it also reduces the surface area of the alveoli
What is the role of the xylem and what is its structure like?
The xylem transports water and mineral ions from the roots to the other parts of the plant. It is a hollow tube of dead cells and walls thickened by lignin
What is the role of the phloem and what is its structure like?
The phloem transports sucrose and amino acids from where they are produced or stored, to where they are needed. It’s a tube of living cells with small holes through which substances can move
What do lymphocytes do?
They produce antibodies which are proteins with a complementary shape to the antigens on the surface of pathogens
