Pre Flashcards
What is one structural role of protein in living organisms?
Production of hair, skin, and nails.
Why do organisms need nitrogen?
Essential for building DNA, RNA, and protein.
What family of plants has a symbiotic relationship with nitrogen-fixing bacteria?
Legume plants.
What is a biological similarity between the nitrogen cycle and the carbon cycle?
Both rely on microorganisms.
What is meant by the term genetic engineering?
Artificial manipulation of genes.
What happens in the isolation stage of genetic engineering?
Target gene from donor is identified and removed, plasmid from bacterium is removed and acts as a vector.
What happens in the expression stage of genetic engineering?
The gene causes the production of a protein (product).
What is the function of plasmids in genetic engineering?
Act as vectors to transfer foreign DNA into host cells, enabling gene cloning and expression. They also contain antibiotic resistance markers for identifying modified cells.
What enzyme is involved in the ligation stage of genetic engineering?
DNA ligase.
What is one application of genetic engineering in animals?
Production of genetically modified (GM) animals for medical research, such as mice engineered to model human diseases (e.g., cancer, Alzheimer’s).
What is one application of genetic engineering in microorganisms?
Production of insulin. Genetically modified E. coli bacteria are used to produce human insulin for diabetes treatment.
How do valves help move blood through veins?
Prevent back flow of blood.
How do muscle fibres help move blood through veins?
Allow expansion to increase blood flow and can withstand pressure; the elastic fibres reshape the vessel.
Name the type of tissue that lines blood vessels
Endothelium
State a function of the lymphatic system
Returns excess tissue fluid from cells to the bloodstream
Give a way lymph differs from blood
Blood: red as it contains haemoglobin in red blood cells, contains red blood cells (RBCs), which are responsible for carrying oxygen throughout the body.
Lymph: pale yellow, consists of white blood cells (mainly lymphocytes), fats, and excess tissue fluid but does not contain red blood cells.
In which zone of the root tip is water absorbed from the soil?
Root hairs
Name the process by which water is absorbed from the soil
Osmosis
Name the vascular tissue that transports water in roots
Xylem
Give one way the xylem is adapted to transporting water
By having lignified cell walls, which provide strength and prevent collapse under pressure.
Name the process by which minerals are absorbed from the soil
Active transport
Write a sentence on how mature red blood cells are adapted to their function
They are disc shaped which increases their surface area, this allows more oxygen to be transported around the body.
Write a sentence on why turgor pressure is important to plants
Turgor pressure is important to plants as it helps maintain cell shape and rigidity, preventing wilting. It also supports plant growth by aiding in cell expansion and nutrient transport.
Describe how you investigated the effect of heat denaturation on the enzyme catalase
Blend celery with water, then filter to extract the catalase solution. Boil one portion of the catalase solution for 5 minutes to denature it, while keeping another portion at room temperature as a control. Add equal volumes of hydrogen peroxide and pH buffer to two separate test tubes. To one test tube, add the boiled catalase, to the other, add the unboiled (active) catalase. Measure the foam (oxygen bubbles) produced over a fixed time (e.g., 1 minute) using a graduated cylinder.
Compare the results in the experiment and in the control
The active catalase produces bubbles, indicating oxygen release. The boiled catalase shows little to no bubbles, proving heat denaturation has inactivated the enzyme. Boiling denatures catalase, causing a loss of enzyme activity, as seen in the reduced oxygen bubble production.
Name one type of adaptation necessary for organisms to survive
A behavioral adaptation like bears hibernating.
Give two factors which might affect the population size of an animal
Disease and availability of food.
Outline the role of microorganisms in pollution control
Decomposing Organic Waste: Microorganisms like bacteria and fungi break down organic matter in waste, such as sewage or agricultural runoff, converting harmful substances into less toxic compounds.
Describe the role of electrons in pathway 1
They move along the electron acceptors and lose energy as they go along, this energy is ATP which is used to form glucose.
Describe how openings in a leaf are controlled
Opening of Stomata (Daytime or When Needed for Gas Exchange): Water enters the guard cells by osmosis, causing them to swell, this increases their turgor pressure, making them turgid, the swelling forces the stomata to open, allowing gas exchange.
Closing of Stomata (Nighttime or to Prevent Water Loss): Water leaves the guard cells by osmosis, causing them to shrink, this decreases their turgor pressure, making them flaccid. The stomata then close, reducing water loss (transpiration).
Explain the term evolution
Inheritable change within a population in response to a change in the environment over time, giving rise to a new species.
State Mendel’s laws of segregation and assortments
Law of segregation: organisms contain two alleles for every trait, these alleles separate at gamete formation, each of which containing one copy of each allele.
Law of assortments: either member of a pair of alleles can pass into a gamete with either member of another pair of alleles, more variation occurs as a result.
Explain the term DNA profiling
Making and examining a pattern of bands from the DNA of one person which can be compared with the DNA profile of another person.
Give an example of mechanical and surgical contraception
Mechanical: condoms
Surgical: vasectomy
Name the structure formed after a morula
Blastocyst
Identify each of the three germ layers
Ectoderm, mesodermal, endoderm
Name a structure of the adult body that forms from each germ layer
Ectoderm: skin
Mesoderm: muscle
Endoderm: internal organs eg liver
What hormone produced by the pituitary gland stimulates the production of sperm cells?
FSH
How could this trial be unethical and harmful?
It is possibly harmful as caffeine is a drug, they should ensure the safety of patients as caffeine can cause insomnia, nausea and nervousness. It can be especially dangerous as either the tester or patient know if they have the drug or placebo.
What term is used to describe organisms whose cells contain a membrane-bound nucleus?
Eukaryotes
What is tissue culture?
The growth of cells in or on a sterile nutrient medium outside an organism, in vitro.
State one requirement for successful tissue culture
Sterile environment
Give one application of tissue culture
Micropropagation
Describe how cell division takes place in animal cells and plant cells at the end of mitosis
Animal cell: groove forms in cytoplasm called cleavage furrow which deepens until it splits into 2 identical cells.
Plant cell: cell plate forms from the vesicles in plant cells, a middle lamella forms in the cell plate to divide the two identical cells.
