GCSE Biology paper 1 2023

Question 1

What do both animal plant cells have- Eukaryotic cells?

Answer 1

A nucleus

Question 2

What does a prokaryotic cell have instead of a nucleus that contains its DNA (genetic material)?

Answer 2

A single loop of DNA/ Plasmid

Question 3

What is an example of a Prokaryotic cell?

Answer 3

Bacteria/ bacterium

Question 4

What are the similarities between eukaryotic and prokaryotic cells?

Answer 4

• They both have a cell wall (only plant cells, not animal cells) and a cell membrane
• They both have ribosomes

Question 5

What are the differences between eukaryotic and prokaryotic cells?

Answer 5

• Eukaryotic cells are much bigger than prokaryotic cells
• Prokaryotic cells do not contain any membrane- bound organelles
• Prokaryotic cells contain their genetic material in a single loop of DNA, aka- a plasmid
• Eukaryotic cells contain their genetic material in the nucleus
• Prokaryotic cells are unicellular, whilst eukaryotic cells are mostly multicellular

Question 6

What are the different functions of each part of an animal cell?

Answer 6

• Cell membrane- controls what leaves and enters the cell
• Cytoplasm- jelly- like substance where chemical reactions take place
• Nucleus- where the genetic material/ DNA is stored (chromosomes)
• Ribosomes- where protein synthesis takes places
• Mitochondria/on- where energy is released via aerobic respiration

Question 7

What are the different functions of each part of a plant cell?

Answer 7

• Cell wall- provides a rigid structure for the cell and prevents bursting of the cell and is made of cellulose- to keep the cell wall strong
• Permanent vacuole- contains cell sap
• Chloroplasts- contains chlorophyll which gives the leaves a green colour and is the site of photosynthesis
• Cell membrane
• Mitochondria/ on
• Ribosomes
• Nucleus
• Cytoplasm

Question 8

How to calculate magnification of a cell?

Answer 8

Size of image/ size of real(actual) object

-can use IAM triangle

Question 9

What happens during the cell cycle- mitosis?

Answer 9

• Stage 1- the cell grows and chromosomes replicate
• Stage 2- one set of chromosomes is pulled to each end of the cell (by the spindle fibres)
• Stage 3- the cytoplasm and cell membrane divide to form two new identical daughter cells

Question 10

Which process makes two identical new body cells for growth and repair?

Answer 10

Mitosis

Question 11

What is differentiation?

Answer 11

When stem cells differentiate into specialised cells

Question 12

What is fertilisation?

Answer 12

When the sperm meets the egg and fertilises it

Question 13

A cell divides to form 2 new cells every 24 hours, how many days will it take for the original cell to divide into 8 cells?

Answer 13

1) 24 hours= 1 day
2) After day 1= 2 new cells
3) After day 2= 4 new cells
4) After day 3= 8 new cells
=3 days
(tip= always draw question out to help visualise)

Question 14

What is the chemical that genetic material is made from?

Answer 14

DNA

Question 15

What is one section of genetic material on a chromosome called?

Answer 15

A gene

Question 16

Explain how a transplant of bone marrow cells can help to treat medical conditions?

Answer 16

1) Bone marrow cells differentiate into red blood cells (another type of cell)
2) So therefore this will help cure diseases that require new red blood cells- Anaemia

Question 17

Describe three differences between the processes of mitosis and meiosis

Answer 17

• Mitosis produces 2 daughter cells, whilst meiosis produces 4 daughter cells
• There is only one cell division in mitosis averaging at around every 24 hours, whereas in meiosis there are 2 cell divisions
• Mitosis happens in somatic (body) cells, whilst meiosis happens in gametes
• Mitosis produces diploid cells- 46 chromosomes, whereas meiosis produces haploid cells- 23 chromosomes
• Mitosis produces genetically identical cells, whereas meiosis produces genetically different cells