Parts Of Cells (Structure And Function)

Question 1

Function of Nucleus

Answer 1

1) Controls ALL activities of the cell

2) Where the genetic code (DNA) of the cell is stored replicated and copied to RNA.

Question 2

Structure of nucleus

Answer 2

. Filled with Genetic Material (DNA)
. Surrounded by Rough ER
. Has a nucleolus inside
. Has a membrane

Question 3

Function of Nucleolus

Answer 3

. Site of ribosome production. Composed of RNA and proteins

Question 4

Function of Nuclear Envelope

Answer 4

. A double membrane which compartmentalises the nucleus and prevents damage and also protects DNA

Question 5

Structure of Rough Endoplasmic Reticulum

Answer 5

Covered with ribosomes and consists of an interconnected system of flattened sacs. System of hollow tubes and membrane bound sacs

Question 6

Structure of Smooth Endoplasmic Reticulum

Answer 6

Similar to Rough ER but lack ribosomes. Has a system of interconnected tubules

Question 7

Function of Rough Endoplasmic Reticulum

Answer 7

Transports protein that were made on the attached ribosomes. Some of the proteins will be secreted by the cell whilst the others will be placed on the surface of the cell membrane

Question 8

Function of Smooth Endoplasmic Reticulum

Answer 8

Responsible for carbohydrate and lipid synthesis and storage

Question 9

Structure of Golgi Apparatus

Answer 9

. Stack of flattened, membrane bounds in sacs (cisternae)

. These are continuously formed from ER at one end and budding off as Golgi vesicles at the other

Question 10

Function of Golgi Apparatus

Answer 10

. Allows internal transport
. Receives proteins from RER
. Modifies and processes molecules (such as new lipids and proteins) and packages them vesicles
. These maybe secretory vesicles (if proteins need to leave the cell) or lysosomes (which stay in the cell)
. Makes lysosomes
. Lipid synthesis

Question 11

Structure of ribosomes

Answer 11

. A 2 subunit organelle 
. Made from RNA and protein 
. No membrane 
. Very small (22nm in diameter)
. Found free floating in cytoplasm or attach in rough ER

Question 12

Function of ribosomes

Answer 12

. Is where protein is made

. They assemble amino acids into protein in chains using mRNA

Question 13

Structure of mitochondria

Answer 13

. Oval shape and surrounded by 2 membranes
. Inner membrane forms finger-like structure called Cristae which increases SA
. Solution inside is called a matrix which contains enzymes for respiration
. Mitochondrial DNA: Small amounts of DNA enable mitochondria to reproduce and create enzymes

Question 14

Function of Mitochondria

Answer 14

. Site of aerobic respiration

. As a result of respiration, they produce ATP (energy carrier in cells)

Question 15

Structure of lysosomes

Answer 15

. They are spherical sacs surrounded by a single membrane

Question 16

Function of lysosomes

Answer 16

. They contain powerful hydrolytic digestive enzymes known as lysozymes
. Their role is to break down worn out components of the cell or digest invading cells

Question 17

Structure of Centrioles

Answer 17

. A component of a cytoskeleton, composed of many microtubles
. Small hollow cylinder that occur in pairs next to the nucleus in animal cells only
. Each centriole contains a ring of 9 microtubules

Question 18

Function of Centrioles

Answer 18

. Makes a copy of itself during cell division and then helps to form the spindle in cell division

Question 19

Cilia Structure

Answer 19

. 2 central microtubes (black circles ) surrounded by nine pairs of nanotubes arranged like a shell (Allows movement)
. Has hair like extensions

Question 20

Cilia Function

Answer 20

. Sensory function (eg nose) beat creating a current to move mucus/fluid/objects

Question 21

Plasma Membrane Structure

Answer 21

. The membrane found on the surface of animal cells and inside the cell wall of plant and prokaryotic cells
. A phospholipid bilayer
. Composed of proteins and lipids

Question 22

Plasma membrane function

Answer 22

. Regulates the movement of substances into and out of the cell
. Contains receptor molecules which allow it to respond to chemical like hormones

Question 23

Cytoskeleton Structure

Answer 23

. Nanotubes and fibres give the cell Structure
. Microfilaments made from protein Actin
. Formed by the globular protein Tublin

Question 24

Microfilaments function

Answer 24

Responsible for movement of the cell, and cytoplasm during Cytokinesis

Question 25

Microtubules Function

Answer 25

They polymerise to form tubes that determine the shape of the cell. They also act as tracks for organelles moving around the cell

Question 26

Intermediate Fibres function

Answer 26

Gives strength to cell and helps maintain integrity

Question 27

Flagella Structure

Answer 27

Axoneme bends due to the microtubules being anchored at the base

Question 28

Flagella Function

Answer 28

Enables cell mobility

Question 29

Chloroplasts Structure (Plant cells only)

Answer 29

. Double membrane which encloses the stroma
. Stroma contains: Startch grains, lipid stores, DNA, RNA, ribosomes and a series of membrane-bound flattened sacs called thylakoids. Thylakoids stacked together are granum
. Granum contains chlorophyll

Question 30

Chloroplast Function

Answer 30

. Photosynthetic Reactions

Question 31

Cell Wall Structure

Answer 31

. Made of cellulose microfibrils-complex carbohydrate
. Fully permeable to substances
. Thin layer called middle lamella which makes the boundary beaten the adjacent cell walls and ‘cements’ adjacent cells together

Question 32

Cell wall function

Answer 32

. Gives the plant mechanical strength
. Gives plant cell support and its shape
. Contents of plant cell can ‘push’ against the cell wall (turgid cell). This gives the cell (and the whole plant) good plant