2A-2D - Cells and Biological Molecules

Define tissue

a group of cells working together to carry out a specific function

Define organ

a group of tissues working together to carry out a specific function

Define organ system

a group of organs working together to carry out a specific function

How is the labour divided within a cell?

within a cell, labour is divided between organelles

Name 5 parts of an animal cell

nucleus, mitochondria, ribosomes, cell membrane, cytoplasm

Name 8 parts of a plant cell

nucleus, mitochondria, ribosomes, cell membrane, cytoplasm, permanent vacuole, chloroplasts, cell wall

State 2 functions of the nucleus

controls the cell, contains genetic material (in the form of chromosomes)

What is the function of the cytoplasm?

It is where the most of the cell's chemical reactions take place

State the function of mitochondira

they are the site of aerobic respiration

State the function of ribosomes

they are the site of protein synthesis

What is the function of the cell wall and what is it made of?

it provides strength and support. It is made of cellulose

What is the function of the permanent vacuole and what does it contain?

It supports the cell and contains cell sap (a solution of sugars and salts)

What is the function of chloroplasts?

They are the site of photosynthesis

What is the function of the cell membrane?

controls what enters and leaves the cell and separates the cell from its membrane

What chemical elements are present in carbohydrates and lipids?

Carbon, hydrogen, oxygen

What chemical elements are present in proteins?

Carbon, hydrogen, oxygen, nitrogen and sulfur

What are complex carbohydrates like starch and glycogen made up of?

simple sugars

What are proteins made up of?

Amino acids

What two molecules are lipids made up of?

glycerol and fatty acid tails

What are enzymes?

Enzymes are biological catalysts that increase the rate of metabolic reactions

State 4 factors that affect enzyme function?

Temperature, pH, substrate concentration, enzyme concentration

Describe the effect of temperature on the rate of an enzyme controlled reaction?

As the temperature increases, so does the rate of reaction. Once the temperature exceeds the optimum, the enzyme denatures and the rate of reaction decreases.

Why does the rate of an enzyme controlled reaction increase when the temperature increases?

As the temperature increases the particles have more KE. This increases the chance of successful collision between molecules and leading to a reaction

If temperature increases above the optimum, how does this affect enzyme function?

the active site will be distorted as the enzyme denatures and so it will no longer fit the substrate

Describe the effect of pH on the rate of an enzyme controlled reaction

The rate of an enzyme catalysed reaction is fastest at the optimum pH. if the pH is too high or too low, the enzyme will work less efficiently and the active site may be denatured at extremes of pH.

Define diffusion

The net movement of molecules from an area of high concentration to an area of low concentration down their concentration gradient

How does temperature affect the rate of diffusion?

as the temp increases, so does the rate of diffusion as the particles have more KE and move faster

How does the concentration gradient affect the rate of diffusion?

the greater the concentration gradient (the difference between the two areas), the faster the rate of diffusion.

How does the surface area of the membrane affect the rate of diffusion?

as the surface area increases so does the rate of diffusion as there is more space for the particles to move through

Define osmosis

the net movement of water molecules from a high water potential to low water potential gradient across a partially permeable membrane

Define active transport

the movement of molecules from a low concentration to a high concentration against their concentration gradient using energy