cells

Name the subcellular structures

Name the subcellular structures

What are the similarities and differences in animal and plant cells

Similarities:

• Both have a cell membrane

• mitochondria

• Nucleus

• Cytoplasm

• Ribosomes

  Differences:

  ↳Plants have:

• Vacuole

• Chloroplasts

• Cell wall

Function of the nucleus

Contains genetic information (DNA) which controls what happens in the cell

Function of cell membrane

Holds the cell together and controls what can enter and leave the cell

Function of Mitochondria

Provides energy for chemical reactions such as aerobic respiration

Function of ribosomes

Site of protein synthesis

Function of cytoplasm

Where chemical reactions take place

Function of a cell wall

Made of cellulose which gives the cell extra support

Function of chloroplasts

Provides the green pigment (chlorophyll) in leaves for photosynthesis

Function of vacuole

Contains cell sap and is used to store water

Are plant cells eukaryotic or prokaryotic?

Eukaryotic

Are bacteria cells eukaryotic or prokaryotic?

Prokaryotic

Differences between prokaryotic and eukaryotic cells

Prokaryotic:

• Smaller

• Single celled (unicelluar)

• Genetic material is not enclosed in a nucleus

  ↳ Single loop of DNA- may be more than one rings called plasmids

Function of plasmids?

Contains genetic information which can replicate and move between cells

What are specialised cells?

A cell that has a structure that aids its specific function

i.e. shape

How are sperm cells specialised?

Function- To carry genetic information to the egg

Features:

- Tail to swim

- Lots of mitochondria for energy

- Acrosome (digestive enzyme)

How are nerve cells specialised?

Function- conduction of electrical impulses

- Dendrites to connect to other nervess

- Axon covered with fatty sheath which speeds up impulse transmission

How are muscle cells specialised?

Function- contracts to move

Features:

- Protein filaments can slide over each other to contract

- Contains many mitochondria to release energy for contraction

How are root hair cells specialised?

Function- to absorb water and mineral ions from the soil

Features:

- Large surface area → increases the rate of water uptake by osmosis

- Large vacuole to aid water absorbtion

- Thin walls → shorter diffusion path

- Mitochondria → releases energy for the active transport of mineral ions

How are xylem cells specialised?

Function- transports water and dissolved ions

Features:

- Hollow tube to move water and mineral ions

- Strengthened with lignin spirals

How are phloem cells specialised?

Function- transports dissolved sugars and amino acids

Features:

- Sieve plates separate the cells but allow the movement of sugars

- Companion cells keep phloem alive and release energy to move sugars

Define cell differentiation

When a cell changes to become a specialised cell

What are meristem cells?

Unspecialised cells that can differentiate into any cell needed by the plant in regions where growth is (tips of roots and shoots)

Name the 2 stem cells (in animals)

Embryonic stem cells- found in an early embryo and are able to divide continuously into most adult cells

Adult stem cells- found in a mature organism and are able to replenish differentiated cells that need to be replaced i.e. bone marrow- form white and red blood cells