2.1.1 structure of eukaryotic cells

Question 1

Structure and function of cell-surface membrane

Answer 1

Phospholipid bilayer with embedded proteins etc

Selectively permeable - enables control of passage of substances in and out of cell

Barrier between internal and external environment of cell

Question 2

Structure and function of nucleus

Answer 2

Nuclear envelope, nuclear pores, nucleolus, DNA/chromatin

Controls the cells activity through transcription on mRNA

Nuclear pores allow substances e.g. mRNA to move between the nucleus and cytoplasm

Nucleolus makes ribosomes which are made up of proteins and ribosomal RNA

Question 3

Structure and function of mitochondria

Answer 3

Double membrane - inner membrane folded to form cristae. Matrix containing small 70S ribosomes, small circular DNA and enzymes involved in aerobic respiration (glycolysis)

Site of aerobic respiration in which ATP is produced

Question 4

Structure and function of Golgi apparatus

Answer 4

3 or more fluid membrane bound sacs with vesicles at edge

Receives protein from RER

Modifies/processes protein e.g. adds carbohydrates/sugars

Packages into vesicles e.g. for transport to cell surface membrane for exocytosis

Also makes lysosomes

Question 5

Structure and function of lysosomes

Answer 5

Type of golgi vesicle containing lysozymes- hydrolysis enzymes

Release of lysozymes to hydrolyse pathogens to worn out cell components

Question 6

Structure and function of ribosomes

Answer 6

Float free in cytoplasm or bound to rER, not membrane bound. Made from 1 large and 1 small subunit

Site of protein synthesis, specifically, translation

Question 7

Structure and function of rough endoplasmic reticulum

Answer 7

Ribosomes bound by a system of membranes

Folds polypeptides to tertiary structure

Packages to vesicles, transport to the Golgi apparatus

Question 8

Structure and function of smooth endoplasmic reticulum

Answer 8

Similar to rER but without ribosomes - system of membranes

Synthesises and processes lipids

Question 9

Structure and function of chloroplasts

Answer 9

Plants and algae

Thylakoid membranes are stacked up in some parts to form grana, which are linked by lamellae. These sit in the stroma and are surrounded by a double membrane.

Also contains starch granules and circular DNA

Chlorophyll absorbs light for photosynthesis to produce organic substances

Question 10

Structure and function of cell wall

Answer 10

Made mainly of cellulose in plants and algae and of chitin in fungi

Rigid structure surrounding cells in plants, algae and fungi, prevents the cell changing shape and lysis

Question 11

Structure and function of cell vacuole

Answer 11

Contains cell sap - a weak solution of salts and sugars. Surrounding membrane is called the tonoplast

Maintains pressure in the cell (stops wilting)

Stores/isolates unwanted chemicals in the cell

Question 12

Specialised cell

Answer 12

The most basic structural/functional subunit in all living organisms; specialised for a particular function

Question 13

Tissue

Answer 13

Group of organised specialised cells; joined and working together to perform a particular function; often with the same origin

Question 14

Organ

Answer 14

Group of organised different tissues; joined and working together to perform a particular function

Question 15

Organ system

Answer 15

Group of organised organs; working together to perform a particular function

Question 16

Epithelial cells in small intestine adaptations

Answer 16

For efficient absorption; villi and micro villi increase surface area

Lots of mitochondria to provide energy e.g. for active transport