Levels of Organisation & Cell structure

_______ are the basic building blocks of all living organisms

Cells

Unicellular organisms are made from ____ cell

one

multicellular organisms are made up of _____________ of cells

collections

Cells are made up of structures called _____________

organelles

Cells are ______________ to carry out particular functions

specialised

specialised cells form _________

tissues

Define organelles

• Specialised structures within a cell that carry out specific functions

Define cells

• Basic structural and functional units of all living organisms

Define tissues

• A group of similar cells that work together to carry out a particular function

Define organs

• A structure made up of different tissues working together to perform a specific function

Define organ systems

• A group of organs that work together to carry out a particular function

What are the organs in the shoot system

• Leaf

• Stem

• Flower

• Fruit

What are the tissues in the shoot system

• Epidermis

• Mesophyll

• Xylem

• Phloem

What are the tissues in the root system?

• Xylem

• Phloem

What are the organs in the root system?

• Root

• Tuber

What are the organs in the digestive system

• Oesophagus

• Stomach

• Small intestine

• Large intestine

What are the tissues in the digestive system

• Muscle

• Connective

• Nerve

• Epithelial

What are the tissues in the circulatory system?

• Muscle

• Connective

• Nerve

• Epithelial

• Veins

• Arteries

What are the organs in the circulatory system?

Heart

What are the organs in the respiratory system?

• Trachea

• Lungs

What are the tissues in the respiratory system?

• Connective

• Muscle

• Epithelial

What are the tissues in the exceratory system?

• Muscle

• Connective

• Nerve

• Epithelial

What are the organs in the exceratory system?

• Lungs

• Kidneys

• Skin

What are the organs in the nervous system

Brain

Spinal cord

What are the tissues in the nervous system

nerves

What are the organs in the reproductive system?

• Ovary

• Uterus

• Testes

What are the tissues in the reproductive system?

• Muscle

• Connective

• Nerve

What is the fucntion of the nucleus?

• Contains genetic material (chromosomes)

What is the fucntion of the cytoplasm?

• Site of many chemical reactions

• Contains water and many solutes

What is the fucntion of the cell membrane?

• Controls substances entering and leaving the cell

What is the function of the cell wall?

• Gives the cell extra support and defines its shape, prevents bursting

What is the function of mitochondria?

• Site of aerobic respiration

What is the function of Chloroplasts?

• Site of photosynthesis

• Contains chlorophyll to absorb light for photosynthesis

What is the function of ribosomes?

site of protein synthesis

What is the function of the vacoule?

• Contains cell sap (water with dissolved solutes)

• Provides support to plant cells, helping them to stay firm

What are the main sub cellular structures/organelles in animals?

• The nucleus: contains genetic material

• Cell membranes: controls what enters and leaves the cell

• Mitochondria: site of aerobic respiration

• Ribosomes: site of protein synthesis

• Cytoplasm: chemical reactions take place in this jelly-like substance

What are some sub cellular structures/organelles that a plant cell has but animals cell do not have?

• A cell wall made of cellulose: gives the cell shape and protection

• A permanent vacuole filled with cell sap: pushes the cytoplasm against the cell wall, keeping the cell turgid

• Plant cells found in the leaf and stem may also contain chloroplasts: the site of photosynthesis

Define cell differentiation

Cell differentiation is the process by which an unspecialised cell becomes specialised to carry out a particular function.

What are speciialised cells?

• Specialised cells are those that have developed certain characteristics that allow them to perform particular functions. Developing these characteristics is controlled by genes in the nucleus

______ ______ are undifferentiated (unspecialised) cells that can divide by ________ to form more stem cells

Stem cells, mitosis

undifferentiated cells are called _______ _____ ______ in humans

adult stem cells

What is the use of adult stem cells?

they are mainly involved in replacing and repairing cells, such as blood or skin cells

What are adaptations of cilated cells?

• Ciliated cells move mucus in the trachea and bronchi

• They have hair-like extensions called cilia, which beat to transport mucus and trapped particles toward the throat

What are adaptation of nerve cells?

• Nerve cells conduct impulses and are long, allowing communication between different parts of the body and the central nervous system

• Their axons are covered in a fatty sheath that insulates and speeds up nerve transmission

What are adaptations of red blood cells?

• Red blood cells transport oxygen efficiently due to their biconcave shape, which provides a high surface area to volume ratio for oxygen diffusion

• Red blood cells are packed with the protein haemoglobin, which transports oxygen from the lungs to the rest of the body. Red blood cells do not have a nucleus, maximising space for haemoglobin to transport oxygen

What are adaptations of root hair cells?

• Root hair cells absorb water and mineral ions from the soil

• Root hair cells have long extensions to increase surface area for maximum absorption, and their thin walls help water move quickly through them

What are adaptations of palisade mesophyl cells?

• Palisade mesophyll cells are found in the leaf and are adapted for photosynthesis

• Palisade mesophyll cells contain many chloroplasts

• The cells are column-shaped and tightly packed together beneath the upper epidermis of the leaf to maximise light absorption for photosynthesis

Q: Describe what happens when a stem cell divides.

A: It can produce identical undifferentiated stem cells (self-renewal) or cells that differentiate into specialised types.

Give one place in the human body where stem cells are found.

Bone marrow.

Explain one difference between embryonic stem cells and adult stem cells.

Embryonic stem cells can turn into any type of cell, but adult stem cells can only turn into a limited range.

Describe why embryonic stem cells are useful in medicine.

They can become any type of cell, so they can be used to replace many different damaged tissues.

Explain how stem cells can be used to treat disease.

They can divide and differentiate into healthy cells to replace damaged or faulty cells.

A patient receives stem cells from a donor. Explain why their body might reject these cells.

The cells have different antigens, so the immune system recognises them as foreign and attacks them.

Explain why a patient may need to take immunosuppressant drugs after a stem cell transplant.

To stop the immune system rejecting the donor stem cells.

Explain why using the patient’s own stem cells reduces the risk of rejection.

The cells have the same antigens, so the immune system does not recognise them as foreign.

Give one risk of using stem cells in medicine.

They could form tumours or cancer.

Give another risk of stem cell therapy.

Cells could be infected with viruses.

Explain one ethical issue with the use of embryonic stem cells.

Embryos are destroyed to obtain the cells, and some people believe this is wrong because embryos are potential human lives.

Some people support the use of stem cells, others do not. Explain why.

Some support it because it can treat serious diseases, while others oppose it because embryos are destroyed.

Give one advantage of using stem cells in medicine.

They can replace damaged cells and treat diseases.

Give one limitation of adult stem cells.

They can only form a limited range of cell types.