Module 1- Intro To Cells

Question 1

How many cells are there approximately in the human body?

Answer 1

Around 50 million million (50 trillion) cells

Question 2

What are cells regarded as in biological terms?

Answer 2

The basic unit of life

Question 3

What can the human body be thought of as?

Answer 3

A large colony of cells

Question 4

What are the three major areas into which cells are traditionally divided?

Answer 4

• The nucleus
• The cytoplasm
• The plasma membrane

Question 5

What is the location of DNA in a cell?

Answer 5

Nucleus

The nucleus houses the genetic material of the cell.

Question 6

What is one of the main functions of the nucleus?

Answer 6

Controls cellular activity

The nucleus regulates various cellular processes and functions.

Question 7

What separates the nucleus from the cytoplasm?

Answer 7

Nuclear envelope

The nuclear envelope is a double-layered, porous membrane.

Question 8

True or False: The nuclear envelope is a single-layered membrane.

Answer 8

False

The nuclear envelope is double-layered.

Question 9

What does DNA stand for?

Answer 9

Deoxyribonucleic acid

Question 10

What is the primary function of DNA?

Answer 10

Determines the majority of human traits

Question 11

What are the building blocks of DNA?

Answer 11

Nucleotides

Question 12

What is the characteristic shape of DNA?

Answer 12

Double helix

Question 13

How is DNA usually organized in the cell?

Answer 13

Wrapped around histone proteins

Question 14

True or False: DNA has a single spiral structure.

Answer 14

False

Question 15

Fill in the blank: DNA is composed of building blocks called _______.

Answer 15

nucleotides

Question 16

What role do histone proteins play in relation to DNA?

Answer 16

Function like bobbins or spools

Question 17

What happens to DNA when cells prepare to divide?

Answer 17

The DNA is wound-up very tightly and begins to fold up upon itself

This process is similar to an elastic band being wound up between two pens.

Question 18

What are chromosomes?

Answer 18

Thread-like structures observed within the nucleus formed from tightly wound DNA

Chromosomes are visible during cell division.

Question 19

True or False: Chromosomes are only visible in the nucleus when a cell is not dividing.

Answer 19

False

Chromosomes become visible when DNA is tightly wound during cell division.

Question 20

Fill in the blank: The tightly wound DNA observed during cell division is called _______.

Answer 20

chromosomes

Question 21

How many pairs of chromosomes do human cells usually have?

Answer 21

23 pairs

This gives a total of 46 chromosomes, known as the diploid number.

Question 22

What are the first 22 pairs of chromosomes in humans called?

Answer 22

Autosomes

Autosomes appear the same in both sexes.

Question 23

What are the sex chromosomes in humans?

Answer 23

XX (female) and XY (male)

The 23rd pair consists of these sex chromosomes.

Question 24

What is a karyograph?

Answer 24

Photographs of chromosomes arranged in pairs according to size

Karyographs are used to determine an individual’s karyotype.

Question 25

What is a karyotype?

Answer 25

An individual's chromosomal makeup ## Footnote Karyotypes are determined using karyographs.

Question 26

True or False: Spermatozoa and ova are exceptions to the usual number of chromosomes in human cells.

Answer 26

True ## Footnote Spermatozoa and ova have a haploid number of chromosomes.

Question 27

Fill in the blank: The diploid number of chromosomes in human cells is _______.

Answer 27

46

Question 28

What can healthcare professionals determine from a persons karyotype

Answer 28

If the correct (diploid) number of chromosomes are present If there are missing or extra chromosomes (aneuploidy) The sex of an individual If there are extra or missing pieces of chromosomes

Question 30

What are karyographs most often prepared from

Answer 30

Cells of unborn babies harvested through amniocentesis

Question 31

What is amniocentesis

Answer 31

When amniotic fluid is collected using a needle

Question 32

Why do they use amniotic fluid

Answer 32

Since the foetus is suspended in this medium it will contain foetal cells which have detached

Question 33

What will the cells in the amniotic fluid be in a state of

Answer 33

Active cell division and have visible chromosomes within their nuclei

Question 34

What is a common disease revealed during amniocentesis

Answer 34

Down syndrome

Question 35

In 95% of cases how many copies are there of blank chromosome

Answer 35

There are 3 copies of the 21st chromosome- trisomy 21

Question 36

What does the extra chromosome result in with Down syndrome

Answer 36

Alters the course of development and causes characteristic clinical features

Question 37

What are the statistics of down syndrome

Answer 37

1/800 live births

Question 38

What about the mother will affect the likelihood of a child being born with downsyndrome?

Answer 38

Age of the mother

Question 39

Clinical features of Down syndrome

Answer 39

Single transverse palmar crease (simian line) Flattened facial features and large gap between the big toe and second toe Macroglossia (enlargement of the tounge) Pronounced epicanthal folds around the eyes Brushfield spots Septal defects

Question 41

What can macroglossia lead to

Answer 41

Interfere with swallowing and impaired speech

Question 42

What are brushfield spots

Answer 42

Observed as pale spots in the iris

Question 43

What are septal defects

Answer 43

Hole in the heart They can allow a mixing of the oxygenated blood on the left hand side of the heart and the deoxygenated blood on the right have side

Question 44

What is patau syndrome

Answer 44

Caused by extra copy of chromosome 13 Usually results in incomplete brain development Missing eyes Cleft palate Occurs approx. 1/10,000 births with most babies dying soon after birth

Question 45

What is the cytoplasm

Answer 45

Region of a cell between the nuclear envelope and the plasma membrane

Question 46

What does cytoplasm consist of

Answer 46

System of interconnected flattened membranes called the endoplasmic reticulum (ER)

Question 47

What are the two types of ER

Answer 47

Rough ER - due to presence of ribosomes is the major site of protein synthesis Smooth ER - lacks ribosomes and is major site of lipid (fat) synthesis

Question 48

What is the cytosol

Answer 48

An aqueous solution within the cytoplasm

Question 49

What makes up cytosol

Answer 49

Complex mixture of water salts sugars amino acids and growth factors