SB1a - SB1c Key Concepts In Biology

Question 1

What does magnification of x30 On a microscope mean

Answer 1

It means it makes things 30x bigger

Question 2

Who used a two lens microscope to discover cells and when

Answer 2

Robert Hooke in 1665

Question 3

What are the two lenses of a microscope called

Answer 3

Objective lens and eyepiece lens

Question 4

How do you workout the magnification of a microscope

Answer 4

Eyepiece lens x objective lens

Question 5

What does the detail obtained by a microscope depend on

Answer 5

The microscopes resolution

Question 6

Resolution definition

Answer 6

The smallest distance between two points that can still be seen as two points

Question 7

State three differences between electron and light microscopes

Answer 7

Electron microscopes use beams of electrons to pass through a specimen to build up an image whereas light microscopes use light

Light microscopes are more affordable and will be the first choice for most average people whereas electron microscopes are extremely expensive and are used in high end companies .

Light microscopes can magnify up to x1500 with resolutions down to 0.0001mm whereas electron microscopes can magnify up to x2,000,000 with resolutions down to 0.000,000,2 meaning they allow us to see cells with great detail and clarity .

Question 8

Who discovered the cells nucleus and when

Answer 8

Robert brown in 1828

Question 9

What is a cell with a nucleus called

Answer 9

A eukaryotic cell

Question 10

Cell membrane function

Answer 10

Controls what enters and leaves the cell and separates one cell from another

Question 11

Cytoplasm function

Answer 11

Contains a watery jelly where most of the cells activities occur

Question 12

Nucleus function

Answer 12

It Controls the cell and its activities . In it are chromosomes which contain DNA. It is especially large in white blood cells

Question 13

What are ribosomes

Answer 13

Tiny round structures found In the cytoplasm that make new proteins for a cell . They are impossible to see with a light microscope . They are impossible to see with a light microscope

Question 14

What are mitochondria

Answer 14

Jelly bean shaped structures which provide energy to the cell . They are difficult to see with a light microscope

Question 15

What are the additional structures plant cells have and their function

Answer 15

Vacuole - stores cell Sap and helps to keep the cell firm
Cell wall - made of cellulose and supports and protects the cell
Chloroplasts - contain chlorophyll which traps energy transferred from the sun , this energy is then used for photosynthesis

Question 16

What are specialised cells

Answer 16

Specialised cells are cells adapted to their function

Question 17

Explain how a cell can be adapted for digestion

Answer 17

The cells that line the small intestine which are their to absorb small food molecules produces by digestion are adapted by having membranes with a lot of tiny folds called microvilli . This increases the surface area of the small intestine . The more area for molecules to be absorbed , the faster absorption happens .

Question 18

How are cells in the pancreas adapted and why

Answer 18

Cells in the pancreas make enzymes needed to digest certain foods. These enzymes are proteins and so the cells the make them are adapted by having a lot of ribosomes.

Question 19

Sexual reproduction in simple terms

Answer 19

When two specialised cells ( gametes ) fuse to create a cell that develops into an embryo

Question 20

Sexual reproduction simple terms

Answer 20

When two male and female gametes fuse to create a cell that develops into an embryo

Question 21

How many chromosomes does a human cell have vs a gamete cell

Answer 21

Human cell has 23 pairs of chromosomes ( 46 in total )

Gamete cell has only 23

Question 22

What is a diploid cell

Answer 22

Cells with two set of chromosomes

Question 23

What is a haploid cell

Answer 23

Cell with one copy of each chromosome

Question 24

State and explain the adaptations of a human female gamete

Answer 24

• haploid nucleus
• cytoplasm is packed with nutrients to supply the egg cell with energy and raw materials for the growth and development of the embryo
• After fertilisation the cell membrane becomes hard to stop other sperm from entering
• jelly coat surrounding the cell membrane to protect the egg cell . The jelly coat also harder so after fertilisation to stop other sperm from entering

Question 25

State and explain the adaptations of a human male gamete

Answer 25

• streamlined head shape to make it an efficient swimmer
• large number of mitochondria arranged in a spiral at the top of the tail to release lots of energy to power the tail .
• at the tip of head is a small vacuole called the acrosome which contains enzymes needed to break down the egg cells jelly coat
• tail waves from side to side allowing the sperm to swim

Question 26

Where does fertilisation occur

Answer 26

In the oviducts of the female reproduction system

Question 27

What is the function of cells in the oviduct and how are they adapted to this function

Answer 27

Their job is to transport the fertilised egg along the oviduct towards the uterus . They are adapted to this function by having hair like cillia which Wave from side to side sweeping substances along .