All topics unsure of

Why might you use an electron microscope?

To visualise objects at a much higher resolution

What is the equation for magnification?

Magnification = size of image/size of object

What is the length of a typical cell?

10 to 30 micrometres

Why do bacteria have flagella?

To enable movement and propel themselves around

Why do bacteria have plasmid DNA?

It has different advantages, such as antibiotic resistance and adaptability?

What is special about bacteria DNA?

They lack a membrane bound nucleus

How does a model show osmosis in a cell?

Showing the movement of water from an area of high water concentration to an area of low water concentration through a partially permeable membrane

What are turgid cells?

Turgid cells are swollen and firm due to water uptake through osmosis

What are flaccid cells?

Flaccid cells are limp and have lost water by the balance

What causes cells to be flaccid or turgid?

Osmotic pressure and the rigidity of the cell wall

What is plasmolysis?

Cells losing water in a hypertonic solution, causing the cell membrane to pull away from the cell wall

What is a hypertonic solution?

A solution that has a higher concentration of solutes compared to the inside of a cell

What is the function of glandular tissue in an organism?

To produce and release substances such as enzymes or hormones

What is the function of epithelial tissue in an organism?

To cover body surfaces and line internal organs to protect and allow absorption or secretion

What is the function of muscular tissue in an organism?

To contract and cause movement of body parts or internal organs

How do enzymes control metabolism?

Speeding up specific chemical reactions in the body without being used up themselves

How does acid in the stomach increase the efficiency of pepsin?

By creating the optimal low pH environment for it to function properly

How does bile emulsifying fats help with digestion?

Breaking them into smaller droplets, increasing the surface area for lipase enzymes to act on

How are white blood cells adapted to their function?

Having a flexible membrane, giving them the ability to change shape to engulf pathogens and produce antibodies or chemicals to fight infections

How do plant transport systems protect against pesticides?

They’re absorbed by a plant’s roots or leaves and transported through the xylem and phloem to protect the entire plant from pests

Why might the distribution of stomata vary?

To balance water loss and gas exchange based on environmental conditions like humidity and light intensity

How are stomata adapted?

With guard cells that open and close to regulate gas exchange and minimize water loss

Why is it so expensive to stop the spread of malaria?

It requires widespread distribution of prevention tools, ongoing medical treatment, vector control, and continuous monitoring

What are risks of chemotherapy?

Damage to healthy cells, weakened immune system, nausea, hair loss, and increased susceptibility to infections

When do cells divide?

When an organism grows or needs to replace damaged cells

Why must new cells contain identical genetic information to the parent cell?

To ensure they function properly like the original cell

What is the series of stages a cell goes through called?

The cell cycle

What happens in the first stages of the cell cycle?

Cell growth and DNA synthesis

What does the DNA do during synthesis?

It produces an exact copy of itself

What does the nucleus contain?

Chromosomes made of DNA molecules

What do chromosomes carry?

A large number of genes

How are chromosomes usually found in body cells?

In pairs

What happens to genetic material during the cell cycle?

It is doubled and then divided into two identical cells

What must a cell do before it divides?

Grow and increase the number of sub-cellular structures like ribosomes and mitochondria

What does the DNA do before mitosis?

It replicates to form two copies of each chromosome

What happens in mitosis?

One set of chromosomes is pulled to each end of the cell and the nucleus divides

What happens after the nucleus divides in mitosis?

The cytoplasm and cell membranes divide to form two identical cells

Why is mitosis important?

It is important for the growth and development of multicellular organisms

What should students be able to recognise about mitosis?

Situations in given contexts where mitosis is occurring

What is a stem cell?

An undifferentiated cell that can give rise to many more cells of the same type or differentiate into other types

Where can stem cells be found in humans?

In embryos and adult bone marrow

What is the function of embryonic stem cells?

They can be cloned and made to differentiate into most types of human cells

What can stem cells from adult bone marrow form?

Many types of cells including blood cells

Where are stem cells found in plants?

In the meristem tissue

What can plant meristem cells do?

Differentiate into any type of plant cell throughout the life of the plant

What conditions might stem cell treatment help?

Diabetes and paralysis

What is therapeutic cloning?

Producing an embryo with the same genes as the patient

Why are stem cells from therapeutic cloning not rejected by the body?

Because they have the same genes as the patient

What are potential risks of using stem cells?

Transfer of viral infection

Why do some people object to stem cell use?

For ethical or religious reasons

What can plant stem cells be used for?

Producing clones of plants quickly and economically

How can stem cells help rare species?

By cloning them to protect from extinction

Why might farmers use cloned crop plants?

To grow large numbers of plants with special features like disease resistance

What are the harmful substances found in tobacco smoke?

Nicotine, tar, carbon monoxide, formaldehyde, and carcinogenic chemicals

How are carnivorous plants adapted to their environment?

They’re adapted to nutrient-poor environments by trapping and digesting insects to obtain essential nutrients

Why do stores of glycogen change with exercise?

Muscles use glycogen as a quick energy source, depleting it during activity and replenishing it afterward

What is the link between protein consumption and concentration of urea in urine?

Higher protein consumption leads to increased breakdown of amino acids, producing more urea that is excreted in urine