Cell Biology Separate Science Paper 1

The genetic material in a plant and animal cell is found in the

Nucleus

Plant and animal cells both have

A nucleus, a cell membrane and cytoplasm

Bacterial cells are also known as

Prokaryotic cells

Plant and animal cells are also known as

Eukaryotic cells

What is the size of bacterial cells compared to eukaryotic cells

Bacterial cells are smalle

Bacterial cells have small rings of DNA called

Plasmids

What is different about the genetic material in bacterial cells compared to animal cells?

It is not enclosed in a nucleus

What material is the cell wall of plant and algal cells made from?

Cellulose

What parts of a plant cell are not found in animal cells

Chloroplasts, Permanent vacuole

What is found in the permanent vacuole of a plant cell

Cell sap

What is the function of the nucleus?

Controls the activities of the cell. It is where the genetic material is found

What is the function of the cytoplasm?

A liquid gel where most chemical reactions take place

What is the function of the cell membrane?

Controls the passage of substances into and out of the cell

What is the function of the mitochondria?

Where aerobic respiration takes place, releasing energy for the cell

What is the function of the ribosomes?

Where protein synthesis takes place

What is the function of the chloroplasts?

Contain chlorophyll

Chlorophyll absorbs light so the plant can make food by photosy

What is the function of the permanent vacuole?

Important for keeping the cells rigid to support the plant

What is the function of the cell wall?

Made of cellulose which helps strengthen the cell and provides support

What is the function of the plasmids?

Where some of the genetic material is found in bacterial cells

What type of microscope would you use to observer ribosomes?

Electron microscope

Give a specialisation of a sperm cell

A large nucleus containing genetic information

A long tail to assist with movement

The mid-section is full of mitochondria to transfer energy for movement

Give a specialisation of a nerve cell

A long axon to carry information over long distances

Numerous dendrites to pass information to neighbouring nerve cells

Give a specialisation of a muscle cell

Contain mitochondria to transfer the energy needed for contracting

Give a specialisation of a root hair cell

Root Hair increases the surface area for efficient water uptake

Large permanent vacuole to maintain water potential

Give a specialisation of a xylem cell

Lignin builds up in the cell wall increasing the strength of the xylem allowing them to withstand the water pressure

The Xylem cells die forming long hollow tubes that allow water move with little resistance up the plant

Give a specialisation of a phloem cell

Cell walls between neighbouring cells breaks down to form sieve plates that allow water to move freely

Phloem cells have relatively few organelles but are kept alive by companion cells

When do most types of animal cells differentiate?

At an early stage

What is different about when most type of plant and animal cells differentiate?

Many types of plant cells retain the ability to differentiate throughout life

In mature animals what is cell division for?

Repair and Replacement

What do we call a cell that has differentiated?

A specialised cell

What is the definition for magnification?

How many times bigger an object appears

What is the definition for resolution?

The ability to distinguish between two separate points

Which has a higher resolving power? An electron or light microscope

Electron microscope

Why are electron microscopes more useful

They can study cells in much finer detail and see more sub-cellular structures

What formula links magnification, size of image and size of real object

Magnification \= Size of image/Size of real object

Which type of microscope has a higher magnification

Electron microscope

What does the nucleus of a cell contain?

Genetic Information / Chromosomes

What are chromosomes made from?

DNA molecules

In body cells how are the chromosomes normally found?

In pairs

Cells divide in a series of stages. What is this called?

The cell cycle

What happens in the first stage of the cell cycle?

The number of sub-cellular structures increases

The DNA replicates

The cell increases in mass

What happens in the second stage of the cell cycle?

Mitosis occurs

The chromosomes are pulled to each end of the cell

The nucleus divides

What happens in the third stage of the cell cycle?

The cytoplasm and cell membrane divide to form two identical cells

What is mitosis important for?

Growth and development

How many cells are produced in mitosis?

2

What are the cells produced in mitosis like?

Identical

What is a stem cell?

An undifferentiated cell of an organism which can become other types of cell

Where are the two main sources of human stem cells?

Embryos, Adult Bone Marrow

In which type of plant tissue do you find cells that can differentiate into any type of plant cell?

Meristem

What conditions could treatment with stem cells help?

Diabetes and Paralysis

What is produced in therapeutic cloning?

An embryo with the same genes as the patient

What is the advantage of using stem cells from embryos for medical treatment?

They will not be rejected from the patient

What are the risks of using stem cells?

The transfer of viral infections

What can the stem cells from meristems in plants be used for?

To produce clones of plants quickly and economically

How can rare species of plants benefit from meristem tissue?

Rare species can be cloned to protect from extinction

How can crop plants benefit from meristem tissue?

Crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers

What is the definition of diffusion?

The movement of molecules down a concentration gradient from a higher to a lower concentration

What substances may be transported into animal cells?

Oxygen

What substance my be transported out of animal cells?

Carbon dioxide, Urea

Which factors affect the rate of diffusion?

The difference in concentration

The surface area of the membrane

The temperature

What is the surface area : volume ratio like in a single celled organism?

High

How are the small intestines adapted as exchange surfaces

Villi to increase the surface area

How are the lungs adapted as exchange surfaces?

Alveoli to increase the surface area

Lots of capillaries for efficient exchange Thin walls to provide a short pathway

How are gills in fish adapted as exchange surfaces?

Excellent blood supply

Large surface area

How are roots adapted as exchange surfaces?

Large surface area

What increases the effectiveness of an exchange surface?

Large surface area

Thin membrane for short diffusion pathway

Efficient blood supply (animals)

Ventilated (Animals for gaseous exchange)

What moves via osmosis?

Water

What is the definition of osmosis?

The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane

What does osmosis require for it to occur?

Partially permeable membrane

What is the definition of active transport?

Active transport moves substances from a more dilute solution to a more concentrated solution (against a concentration gradient)

What does active transport require?

Energy from respiration

Where does active transport occur in plants?

Active transport occurs in the plant root hairs, allowing mineral ions to be absorbed from very dilute solutions in the soil

Why do plants require ions?

Healthy growth

Where does active transport take place in humans?

It allows sugar molecules to be absorbed from low concentrations in the gut into the blood

Why do humans require sugar molecules?

Cellular respiration

Where does the energy in active transport come from?

Respiration

What do we call the process in which bacteria reproduce?

Binary fission

How often will bacteria reproduce?

Once every 20 minutes

When will bacteria reproduce?

Enough nutrients and suitable temperature

Where can bacteria grow?

Nutrient broth or as colonies on an agar plate

At what temperature should cultures be incubated at?

25oC

What do we use to transfer microorganisms to the media?

Inoculating loops

How do you sterilise the inoculating loop?

Passing through a flame

How should the Petri dish be secured?

With adhesive tape on the side and stored upside down