The human body

Question 1

How many cells are in the human body?

Answer 1

There are around 50 trillion cells in the human body

Question 2

Draw and label a human cell

Answer 2

Check against diagram in notes, should include:
Cell membrane, mitochondria, rough endoplasmic reticulum, ribosome, nucleus, golgi apparatus, smooth endoplasmic reticulum, lysosome and cytoplasm

Question 3

Where is DNA stored

Answer 3

DNA is stored in the nucleus

Question 4

What is the nuclear envelope

Answer 4

the nuclear envelope is a double layered porous membrane holding the nucleus

Question 5

What is the role of the nucleolus

Answer 5

The nucleolus makes ribosomes

Question 6

Name the levels of organisation in the human body

Answer 6

Cell, Tissue, Organ, Organ System, Organism

Question 7

What is the structure and function of deoxyribose nucleic acid

Answer 7

DNA is the genetic blueprint that determines most human traits. It is composed of nucleotides wound into a double helix round histone proteins.

Question 8

What are chromosomes

Answer 8

Chromosomes are formed when DNA winds tightly as it prepares to divide

Question 9

How many chromosomes are there is human cells

Answer 9

There are 46 chromosomes in the human body (23 pairs)

Question 10

What are the differences in chromosomes between men and women

Answer 10

The first 22 pairs are autosomes and are the same in men and women. The 23rd are sex chromosomes and are XX in women and XY in men.

Question 11

What is a photograph chromosomes called?

Answer 11

Photographs of chromosomes are called karyographs and they reveal a persons karyotype which can tell if they have the correct number of chromosomes or if there are any extra/ missing chromosomes or bits of chromosomes. They also reveal a persons sex.

Question 12

How are karyographs used in screening in pregnancy

Answer 12

Cells harvested through amniocentesis are used to formed karyographs. Amniotic fluid is collected using a needle which contains detached foetal cells in active cell division with visible chromosomes. A karyograph is formed which shows any chromosomal abnormailities.

Question 13

What is down syndrome

Answer 13

Down syndrome is caused by an extra copy of chromosome 21 (trisomy 21) and it alters the course of development. It occurs in 1 in every 800 births and chance increases with age.

Question 14

What are the clinical features of down syndrome

Answer 14

Single prominent palm crease
Pronounced epicanthal folds
Flattened facial features
Large gap between big and second toe
short 5th finger that curves inwards
Septal defect
Brushfield spots on 
Macroglossia (enlargement of the tongue)
Increased creasing on soles of foot

Question 15

What is patau syndrome

Answer 15

Patau syndrome is caused by an extra copy of chromosome 13 (trisomy 13). Occurs in 1 in 10000 live births.

Question 16

What are the clinical features of patau syndrome

Answer 16

Incomplete brain development, missing eyes, cleft palate

Question 17

What is the cytoplasm

Answer 17

The region between the nuclear envelope and plasma membrane. It is made of cytosol.

Question 18

What us cytosol made up of

Answer 18

Mixture of water, salt, sugar, amino acids and growth factors.

Question 19

What is the endoplasmic reticulum

Answer 19

There are two types of endoplasmic reticulum
the rough endoplasmic reticulum is covered in ribosomes and is the site of protein synthesis
The smooth endoplasmic reticulum is the site of lipid synthesis

Question 20

What is the golgi apparatus

Answer 20

The golgi apparatus received proteins from the rough endoplasmic reticulum and packages them to be exported outside of the cell. It also produces lysosomes.

Question 21

What is a lysosome

Answer 21

Lysosomes are sacs of digestive enzymes. They can be used in the immune system to digest bacteria ingested by neutrophils in phagocytosis.

Question 22

What is a mitochondria

Answer 22

Mitochondria are responsible for cellular respiration. They are the site where oxygen and glucose release energy used to make ATP. They contain their own DNA so they can replicate independently.

Question 23

What is a plasma membrane

Answer 23

Plasma membranes are made of a phospholipid bilayer which is embedded with receptor and channel proteins. It is covered in a layer of glycocalyx which allows the cell to recognise itself. It holds the cell together and regulates the movement of substances. It is also involved in cell signalling the the fluid structure aids phagocytosis.

Question 24

What are the types of cell extensions

Answer 24

Non motile eg microvilli whih increase surface area

Motile eg cillia which move material