eukaryotic cells

Question 1

cell surface membrane description

Answer 1

the membrane found on the surface of animal cells and just inside the cell wall of other cells
made mainly of lipids and protein

Question 2

cell surface membrane function

Answer 2

regulates the movement of substances into and out of the cell
it also has receptor molecules on it, which allow it to respond to chemicals like hormones

Question 3

nucleus description

Answer 3

a large organelle surrounded by a nuclear envelope which contains many pores
the nucleus contains chromosomes which are made from protein-bound linear DNA and one or more structures called a nucleolus

Question 4

nucleus function

Answer 4

the nucleus controls the cell’s activities by controlling the transcription of DNA
DNA contains instructions to make proteins
The pores allow substances to move between the nucleus and the cytoplasm
The nucleolus makes ribosomes

Question 5

Mitochondrion description

Answer 5

They’re usually oval-shaped
Have a double membrane - the inner one is folded to form structures called cristae
Inside is the matrix, which contains enzymes involved in respiration

Question 6

Mitochondrion function

Answer 6

The site of aerobic respiration, where ATP is produced

Found in large numbers in cells that are very active in required a lot of energy

Question 7

Chloroplast description

Answer 7

A small, flattened structure found in plant and algal cells
Surrounded by a double membrane, also has membranes inside called thylakoid membranes
These membranes are stacked up in some parts of the chloroplast to form grana
Grana are linked together by lamellae - thin, flat pieces of thylakoid membrane

Question 8

Chloroplast function

Answer 8

The site where photosynthesis takes place
Some parts of photosynthesis happen in the grana, and other parts happen in the stroma (thick fluid found in chloroplasts)

Question 9

Golgi apparatus description

Answer 9

A group of fluid-filled, membrane-bound flattened sacs

Vesicles are often seen in the edges of the sacs

Question 10

Golgi apparatus function

Answer 10

It processes and packages new lipids and proteins

It also makes lysosomes

Question 11

Golgi vesicle description

Answer 11

A small fluid-filled sac in the cytoplasm, surrounded by a membrane and produced by the golgi apparatus

Question 12

Golgi vesicle function

Answer 12

stores lipids and proteins made by the golgi apparatus and transports them out of the cell via the cell-surface membrane

Question 13

lysosome description

Answer 13

a round organelle surrounded by a membrane, with no clear internal structure
it’s a type of golgi vesicle

Question 14

lysosome function

Answer 14

contains digestive enzymes called lysozymes
These are kept separate from the cytoplasm by the surrounding membrane, and can be used to digest invading cells or to break down worn out components of the cell

Question 15

Ribosome description

Answer 15

a very small organelle that either floats free in the cytoplasm or is attached to the rough endoplasmic reticulum
It’s made up of proteins and RNA
It’s not surrounded by a membrane

Question 16

Ribosome function

Answer 16

The site where proteins are made

Question 17

Rough endoplasmic reticulum description

Answer 17

A system of membranes enclosing a fluid-like space

The surface is covered with ribosomes

Question 18

Rough endoplasmic reticulum function

Answer 18

folds and processes proteins that have been made at the ribosomes

Question 19

Smooth endoplasmic reticulum description

Answer 19

similar to rough endoplasmic reticulum but with no ribosomes

Question 20

smooth endoplasmic reticulum function

Answer 20

synthesises and processes lipids

Question 21

cell wall description

Answer 21

a rigid structure that surrounds cells in plants, algae and fungi
in plants and algae it’s made mainly of the carbohydrate cellulose
in fungi, it’s made of chitin

Question 22

cell wall function

Answer 22

supports cells and prevents them from changing shape

Question 23

cell vacuole description

Answer 23

a membrane-bound organelle found in the cytoplasm of plant cells
it contains cell sap - a weak solution of sugar and salts
the surrounding membrane is called the tonoplast

Question 24

cell vacuole function

Answer 24

helps to maintain pressure inside the cell and keep the cell rigid
This stops plants wilting
Also involved in the isolation of unwanted chemicals inside the cell

Question 25

organelles in specialised cells vary - why?

Answer 25

the organelles in the cell are the ones the cell needs to do it’s job - eg if the cell uses a lot of energy, it’ll needs lots of mitochondria - it if makes a lot of proteins, it’ll need a lot of ribosomes

Question 26

epithelial cell example

Answer 26

in small intestine - specialised to absorb food efficiently

walls of the small intestine have a lot of finger-like projections called villi - these increase surface area for absorption

on the surface of the villi have folds in their cell-surface membranes called microvilli - further increase surface area

also have lots of mitochondria to provide energy for transport of digested food molecules into the cell

Question 27

tissue

Answer 27

specialised cells that are grouped together, to work together to perform a particular function

different tissues work together to form organs