Science Chapter 1

Question 1

Unicellular organisms

Answer 1

Organisms that only have 1 cell.

Question 2

Microscope

Answer 2

An object that you use to study a specimen close up.

Question 3

Diffusion

Answer 3

When particles move from an area of high concentration to an area on low concentration.

Question 4

Specialised cell

Answer 4

A cell that is specialised to do a particular job.

Question 5

A slide

Answer 5

A slide is something that you place your specimen onto before you study it with a microscope.

Question 6

Nuclues

Answer 6

Stores DNA.

Question 7

Cell membrane

Answer 7

Controls what goes in and out of the cell.

Question 8

Mitochondria

Answer 8

Energy is released here by respiration. (Oxygen and food meet.)

Question 9

Cell wall

Answer 9

Strengthens the cell.

Question 10

Chloropast

Answer 10

Contain chlorophyll, which absorbs light energy for photosynthesis.

Question 11

MRS GREN

Answer 11

MRS GREN is an acronym often used to help remember all the necessary features of living organisms: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion and Nutrition.

Question 12

Multicellular organisms

Answer 12

An organism that is made of more than one cell.

Question 13

Cytoplasm

Answer 13

Most chemical processes take place here.

Question 14

Vacuole

Answer 14

They are found in both animal and plant cells but are much larger in plant cells. Vacuoles might store food or any variety of nutrients a cell might need to survive. They can even store waste products so the rest of the cell is protected from contamination.

Question 15

Cells

Answer 15

Organisms are made up of them. Some of them have different functions to others. These are called specialised cells.

Question 16

Resolution

Answer 16

When you look at a digital image or through a microscope you see an image which has a resolution. The greater the resolution, the more detailed the image will be.

Question 17

Magnification

Answer 17

Magnification calculations
We can calculate the length of a magnified object by using the magnification of the lens.
Length of object = length of magnified object ÷ magnification
For example, if a specimen appeared 10mm in length under a microscope with a magnification of 1,000 times, the calculation of the actual length would be:
Length of object = 10 ÷ 1000 = 0.01 mm

Question 18

Rate of diffusion

Answer 18

How quickly particles diffuse.

Question 19

Sperm cell adaptations

Answer 19

The head contains genetic information and an enzyme to help penetrate the egg cell membrane. The middle section is packed with mitochondria for energy. The tail moves the sperm to the egg.

Question 20

Root hair cell adaptations

Answer 20

Long ‘finger-like’ process with very thin wall, which gives a large surface area.

Question 21

Red blood cell adaptations

Answer 21

Thin outer membrane to let oxygen diffuse through easily. Shape increases the surface area to allow more oxygen to be absorbed efficiently. No nucleus, so the whole cell is full of haemoglobin.

Question 22

Egg cell adaptations

Answer 22

Each egg cell has a haploid nucleus - containing only half the number of chromosomes of a normal cell nucleus. It has a large cytoplasm which contains the nutrients and mitochondria needed for mitosis (cell division) after fertilisation. And each egg has a special cell membrane which only allows one sperm to fertilise it.

Question 23

Nerve cell adaptations

Answer 23

The main parts of the nervous system are the central nervous system - the CNS - the brain and spinal cord - and the peripheral nervous system. Nerve impulses are mainly electrical and carried in nerve cells, or neurones.

Question 24

Binary fission

Answer 24

Bacteria reproduction

Bacteria reproduce by binary fission. This means that one cell splits into two new cells. As there is only one parent involved, this is a type of asexual reproduction.

Question 25

What is special about a red blood cell’s outer membrane?

Answer 25

It has a thin outer membrane so that oxygen can diffuse through it easily.

Question 26

Tissue

Answer 26

Tissue makes up organs and is made up of specialised cells.

Question 27

Organ

Answer 27

Organs make up organ systems and are made up of tissues.

Question 28

Organ system

Answer 28

Organ systems are groups of organs that carry out a particular function.