Cellular Physiology 2 - Cytoplasm, Nucleus & Genetics

Question 1

What is the internal environment?

Answer 1

the extracellular fluid in which the cells live

Question 2

What are organelles?

Answer 2

Smaller parts of the cell with specific
functions

Question 3

What is cytoplasm?

Answer 3

Content of the cell outside the nucleus but inside the cell
membrane (area within the membrane)
No genetic material
Houses organelles

Question 4

What is cytosol?

Answer 4

Complex mixture of cytoskeleton, filaments, dissolved
molecules

Question 5

What is the cytoskeleton?

Answer 5

Dense network of protein fibres running through the cytoplasm
Give a cell its shape & provide a basis for movement
Microtubules - Made from tubulin
Microfilaments - Made from actin
Intermediate fibres

Question 6

What are cilia?

Answer 6

Thread-like projections that beat in a regular
fashion to create currents that sweep materials along

Question 7

What are flagella?

Answer 7

Extend to the rear of a cell and push it forward by
snakelike wriggling, or stick out in front and draw it along

Question 8

What is the Endoplasmic reticulum?

Answer 8

The internal delivery system of the cell
2 types of endoplasmic reticulum
Rough ER - Rough appearance due to ribosomes
Makes proteins
Smooth ER – Smooth appearance (No ribosomes)
Makes fats or lipids

Question 9

What are Ribosomes?

Answer 9

Organelles that help in the synthesise proteins
Some ribosomes are found in the cytoplasm - Most are attached to the endoplasmic reticulum
2 subunits – Required for protein synthesis
Large subunit
Small subunit
Units dock together to
make proteins from RNA

Question 10

What are golgi apparatus?

Answer 10

Receives protein & lipid-filled vesicles from endoplasmic reticulum, packages, processes, and
distributes them within the cell or for export out of the cell
Enclose digestive enzymes into
membranes to form lysosomes

Question 11

What are lysosomes?

Answer 11

Break down food (powerful digestive enzymes) into particles the rest of the cell can use and to destroy
old cells or invaders

Question 12

What are Mitochondrion?

Answer 12

Organelle responsible for the generation energy, i.e. ATP
Contains DNA
Can replicate themselves
Bound by a double membrane

Question 13

What is the nucleus?

Answer 13

Separates the genetic material (DNA) from the rest of the cell
It is the largest organelle of the cell
DNA is a blueprint or code for making proteins

Question 14

What is DNA?

Answer 14

Deoxyribonucleic acid – Carrier of genetic information that form chromosomes
Double helix shape – 2 chains of nucleotides
The two strands are antiparallel
The backbone of the DNA molecule is composed
of alternating phosphate groups & sugars

Question 15

What is the function of DNA?

Answer 15

Code for proteins
Storage of genetic information
Self-duplication & inheritance
Expression of the genetic message

Question 16

Information is encoded in the order of the nitrogenous bases I.E?

Answer 16

nucleobases

Question 17

Name the 2 purines.

Answer 17

Adenine and Guanine

Question 18

Name the 2 Pyrimidines.

Answer 18

Thymine and Cytosine

Question 19

What do purines and Pyrimidines form part of?

Answer 19

a nucleotide

Question 20

Purines pair with what?

Answer 20

Pyrimidines

Question 21

Nucleotides form the structural units of what?

Answer 21

DNA & RNA

Question 22

What does Nucleotide pairing do?

Answer 22

Pairing creates the DNA coding sequence

Question 23

Purines pair with pyrimidines, but how?

Answer 23

Paired via hydrogen bonds

Question 24

What is a genome?

Answer 24

The complete set of genetic information in an organism

Question 25

What are genes?

Answer 25

Sequence of nucleotides in DNA

Question 26

What is Ribonucleic acid (RNA)?

Answer 26

Single-stranded | Coding/decoding & regulation/expression of genes

Question 27

What is Messenger RNA (mRNA)?

Answer 27

Replicates the DNA's genetic code

Question 28

What is Transfer RNA (tRNA)?

Answer 28

Reads the strand of mRNA and translates it into a strand of amino acids

Question 29

What is Ribosomal RNA (rRNA)?

Answer 29

Makes polypeptides (assemblies of amino acids) that go to make up proteins

Question 30

In protein synthesis, what is transcription?

Answer 30

Base triplets in DNA serve as template to copy information into a complimentary sequence of codons 1. Promoter - Nucleotide sequence that begins transcription 2. Transcription - Complimentary bases pair 3. Termination Nucleotide sequence that ends transcription

Question 31

In protein synthesis, what is translation?

Answer 31

Nucleotide sequence in mRNA specifies the amino acid sequence of a protein Large sub-unit of ribosome has 2 binding sites for TRNA – A-site & P-site Small sub-unit of ribosome has binding site for mRNA

Question 32

What are the 3 parts of translation?

Answer 32

Initiation, Elongation and Termination

Question 33

In translation, what is Initiation?

Answer 33

mRNA binds to small ribosomal sub-unit Initiator tRNA binds to start codon (AUG) on mRNA (not pictured) tRNA anticodon (UAC) attaches to mRNA codon (AUG) Large ribosomal sub-unit attaches to small ribosomal sub-unit Initiator tRNA fits into P-site

Question 34

In translation, what is Elongation?

Answer 34

Anticodon of incoming tRNA pairs with next codon at A-site Aino acid on tRNA at P-site form peptide bond with amino acid at A site tRNA at P-site leaves ribosome Ribosome shifts by one codon tRNA previously in A-site now in P-site & allows another tRNA to bind to the exposed A-site

Question 35

In translation, what is Termination?

Answer 35

Protein synthesis stops when stop codon enters A-site Completed protein detaches from the final tRNA Ribosome splits into small & large subunits

Question 36

What are telomeres?

Answer 36

DNA sequence found only at the tips of each chromosome Each cell cycle division shortens telomeres Ageing can cause telomeres to erode, including some functional components of the chromosome Shortening of telomeres contributes to cell death Individuals who experience high levels of stress have shorter telomere length

Question 37

What are free radicals?

Answer 37

Unstable molecules which produce oxidative damage by stealing an electron from a stable cell

Question 38

Name 2 clinical ageing disorders.

Answer 38

Progeria Werner Syndrome

Question 39

What are some causes of cancer?

Answer 39

Carcinogens Environmental agents (e.g. radiation, pollution) | Chemical agents (e.g. air, food & water) Oncogenes Cancer causing genes (e.g. ras gene family) Oncogenic virus Viruses that only reproduce when inside the cells they infect (e.g. HPV that causes almost all cervical cancers in women)

Question 40

Name 2 local methods of cancer therapy

Answer 40

Surgery and radiation

Question 41

Name 3 systemic methods of cancer therapy

Answer 41

Chemotherapy Hormone Therapy Targeted therapy

Question 42

What promotes a gradual reduction in cell function?

Answer 42

Ageing

Question 43

What is a group of diseases characterised by uncontrolled or abnormal cell proliferation

Answer 43

Cancer