Structure of eukaryotic cells

Question 1

Nuclear envelope

Answer 1

Is a double membrane that surrounds the nucleus. It controls the entry and exit of material in and out of the nucleus and contains the reactions taking place within it.

Question 2

Nuclear pores

Answer 2

Allow the passage of large molecules such as messengers RNA out of the nucleus

Question 3

Nucleolus

Answer 3

Is a small spherical region within the nucleoplasm. It manufactures ribosomal RNA and assembles the ribosomes

Question 4

Mitochondria

Answer 4

The site of aerobic stages of respiration (ATP) which is made up of a double membrane which controls the entry and exit of materials

Question 5

Cristae

Answer 5

Are extensions of the inner membrane which in some species extend across the whole width of the mitochondrion. These provide a large surface area for the attachment of enzymes

Question 6

Matrix

Answer 6

Makes up the remainder of the mitochondrion. It contains proteins, lipids, ribosomes and DNA that allows the mitochondrion to control the production of their own proteins.

Question 7

Grana

Answer 7

Stacks of up to 100 disc-like structures called thylakoids, within the thylakoids is the photosynthetic pigment chlorophyll. This is where the first stage of photosynthesis occurs

Question 8

Stroma

Answer 8

A fluid-filled matrix where the second stage of photosynthesis takes place

Question 9

Golgi apparatus

Answer 9

responsible for transporting, modifying and packaging proteins and lipids into vesicles for delivery to targeted destinations.

Question 10

functions of golgi apparatus

Answer 10

-add carbohydrates to proteins to form glycoproteins
-produce secretory enzymes, such as those secreted by the pancreas
-secrete carbohydrates such as those used in the making cell walls in plants
-transport, modify nba dpackage lipids
-form lysosomes

Question 11

Lysosomes

Answer 11

Are formed when the vesicles produced by the golgi apparatus contain enzymes such as protease and lipase. They also contain lysozymes enzymes that hydrolyse the cell wall of certain bacteria.

Question 12

Rough endoplasmic reticulum

Answer 12

Has ribosomes present on the outer surfaces of the membranes
- Provides a large surface area for the synthesise of proteins and glycoproteins
- Provide a pathway for the transport of materials, especially proteins throughout the cell

Question 13

Smooth endoplasmic reticulum

Answer 13

Lacks ribosomes on its surface
- synthesises, stores and transports lipids
- synthesises, stores and transports carbohydrates

Question 14

Ribosomes

Answer 14

Small cytoplasmic granules, 80s found in eukaryotic cells, occur in vast numbers (Cytoplasm)
-site of protein synthesis

Question 15

Cell wall

Answer 15

-Characteristic of plant cells
Consists of microfibrils of polysaccharide cellulose, embedded in matrix.
-microfibrils have considerable strength so contribute to the overall strength of the cell wall

Question 16

Specialised cell

Answer 16

a specialised cell have a specific feature to carry out a particular role

Question 17

Differentiation

Answer 17

The process of when unspecialised cells (stem cells) turn into specialised cells

Question 18

Tissue

Answer 18

Many identical specialised cells come together to perform a specific function

Question 19

Organ

Answer 19

A group of tissues that are coordinated to perform a function

Question 20

Organ system

Answer 20

A group of organs that perform a particular function more efficiently

Question 21

Multicellular organism

Answer 21

Organisms that are made up of multiple cells

Question 22

Eukaryotic cell

Answer 22

are larger and have a nucleus bounded by nuclear membranes

Question 23

Chitin

Answer 23

Found in the cell wall of fungi

Question 24

Histone

Answer 24

A protein that provides structural support for each chromosome

Question 25

Structure of eukaryote

Answer 25

-Distinct nucleus with nuclear envelope
-DNA is associated with proteins called histone
-No plasmids +DNA is linear
-Membrane bound organelles (mitochondria)
-Chloroplasts present in plant +fungi
-Ribosomes are larger (80s)

Question 26

The nucleus

Answer 26

Contains the organism’s hereditary material and controls the cell’s activities

Question 27

Nucleoplasm

Answer 27

Is the granular, jelly like material that makes up the bulk of the nucleus

Question 28

Chromosomes

Answer 28

consist of protein-bound linear DNA

Question 29

what are the parts that make up the nucleus

Answer 29

Nuclear envelope, nuclear pores, nucleoplasm, chromosomes and the nucleolus

Question 30

Describe the structure and function of the nucleus.

Answer 30

Structure:
Nuclear envelope and pores/ Double membrane and pores;
2. Chromosomes/ DNA with histones;
3. Nucleolus/nucleoli;
Function:
4. (Holds/stores) genetic information/material
for polypeptides (production)
5. DNA replication (occurs);
6.Transcription (occurs);
7. Production of rRNA/ribosomes;

Question 31

Chloroplasts

Answer 31

organelles that carry out photosynthesis

Question 32

Chloroplast envelope

Answer 32

A double plasma membrane that surrounds the organelle and is highly selective in what it allows to enter and leave

Question 33

How are chloroplasts adapted to carry out photosynthesis

Answer 33

-the granal membranes provide a large surface area for the attachment of chlorophyll, electron carriers and enzymes in the first stage of photosynthesis
-The fluid of the stroma possesses all the enzymes needed to make sugars in the second stage of photosynthesis
-Contain both DNA and ribosomes so they can quickly and easily manufacture some of the proteins needed for photosynthesis

Question 34

What is the endoplasmic reticulum

Answer 34

An elaborate three dimensional system of sheet like membranes spreading through the cytoplasm of the cells. It’s continuous with the outer nuclear membrane and enclose a network of tubules and flattened sacs

Question 35

What are the two types of endoplasmic reticulum

Answer 35

Rough endoplasmic reticulum
smooth endoplasmic reticulum

Question 36

What is the function of lysosomes

Answer 36

-hydrolyse material ingested by phagocytic cells
-release enzymes to the outside of the cell in order to destroy material around the cell
-digest worn out organelles so that useful chemicals they are made up of can be re-used
-completely break down cells after they have died

Question 37

What are ribosomes made up of

Answer 37

-ribosomal RNA
-protein

Question 38

What is the function of the cell wall

Answer 38

• to provide mechanical strength in order to prevent the cell bursting under the pressure created by the osmatic entry of water
  -to allow water to pass along it and so contribute to the movement of water through the plant

Question 39

Vacuole

Answer 39

A fluid filled sac bound by a single membrane
-In a mature plant cell there is usually one large central vacuole
-contains a solution of mineral salts, amino acids and sugars

Question 40

What is the function of the vacuole

Answer 40

-Temporary food store
-The pigment may colour petals to attract pollinating insects
-Support herbaceous parts of woody plants