National 5 Biology

Name five parts of an animal cell?

Nucleus, cytoplasm, cell membrane, ribosomes, mitochondria

Name three structures found in plant cells but not in animal cells?

Chloroplast, Cell wall, Vacuole

What type of cell(s) contain plasmids?

Bacteria

Name the part of the cell that controls the activities of the cell?

Nucleus

What important substances are made by ribosomes?

Proteins

What controls the entry and exit of materials in a cell?

Cell membrane

What is the function of the cytoplasm?

Site of chemical reactions

What is the site of aerobic respiration (a chemical reaction which releases energy from food) in a cell?

Mitochondria

Which types of cell(s) have a cell wall?

Plants, Fungal and Bacterial

Where do you call the fluid-filled sac containing water, sugars and salts which is found in a plant or fungal cell?

Vacuole

What chemical reaction takes place inside a chloroplast uisng energy from the sun?

Photosynthesis

Name the pigment found in chloroplasts which trap light energy from the sun?

Chlorophyll

What is a plant cell wall composed of?

Cellulose

Are plant and bacterial cell walls made of cellulose?

No - only plant

Name two type of cells other than animal and plant.

Fungal and bacterial cells

Name two ways in which bacterial cells are different to the other three types.

Bacterial cells have no nucleus and no organelles except ribosomes.

What do bacteria have instead of a nucleus?

A loop of DNA and circular plasmids.

Which two substances make up the cell membrane?

Phospholipids and proteins

What do you call the movement of molecules from a region of higher concentration to lower concentration (down the concentration gradient).

Diffusion

State two useful substances that cells gain by diffusion

Oxygen, glucose, amino acids

State two waste substances that cells lose by diffusion

Carbon dioxide, urea

What is meant by passive transport?

A type of transport that occurs down the concentration gradient and does not require energy.

What words describe the property of cell membranes whereby they allow only some substances to cross.

semi-permeable / selectively permeable

Why can starch not pass through the cell membrane by diffusion?

It is too large to fit through the cell membrane.

Define osmosis

Osmosis is the movement of water molecules from a region of higher water concentration to a region of lower water concentration through a selectively permeable membrane.

What word is used to describe a plant cell when it is placed in a solution of lower water concentration.

Plasmolysed

What do you call a plant cell that has been placed in a solution of higher water concentration?

Turgid

What happens to an animal cell when it is placed in a solution of higher water concentration?

Burst - because they have no cell wall to maintain the structure.

What kind of solution makes an animal cell shrink?

A lower water concentration.

What kinds of transport moves substances against their concentration gradient and requires energy?

Active transport.

As well as energy, what else does active transport require?

Membrane proteins

Visking tubing is often described as a model cell. Why?

It has a semi-permeable membrane

When investigating osmosis in potato cylinders, what must you do to them before you re-weigh them?

blot them dry to remove excess water

Describe the structure of DNA

Double-stranded helix held by complementary base pairs.

What is DNA made from?

A sequence of bases - A, T, C, G

What are the base pairing rules in DNA?

Adenine-Thymine, Guanine - Cytosine

Three bases together code for what chemicals that make proteins?

Amino acids

Name the molecule which carries a complementary copy of DNA to the ribosomes?

mRNA

What is a gene?

A section of DNA / sequence of bases that codes for a protein

How does DNA determine the structure of a protein?

The base sequence determines amino acid sequence; which determines the shape of the protein.

Name three functions of proteins.

Structural, enzymes, hormones, antibodies, haemoglobin

How do the variety of protein shapes arise?

The different sequences of amino acids.

What are biological catalysts called?

Enzymes

Where can you find enzymes?

In all living cells

What is the function of enzymes?

Speed up chemical reactions

What do we call the part of an enzyme that is complementary to its specific substrate(s)?

Active site

What is the word that describes the fact that each enzyme only acts on one substrate?

Specific

What is formed at the end of an enzyme controlled reaction?

Products (and unchanged enzyme)

What type of reaction is it when an enzyme builds up large molecules from more smaller molecules?

Synthesis

What type of reaction is it when an enzyme breaks down large molecules into many smaller molecules?

Degradation

What enzyme breaks down hydrogen peroxide into water and oxygen?

Catalase

Name the enzyme that breaks down starch to maltose?

Amylase

Draw a graph showing activity of an enzyme against pH, and activity of an enzyme against temperature.

What happens to enzymes at high temperatures and extremes of pH?

They are denatured (shape of the active site is permanently changed) and the rate of reaction decreases.

What word describes the conditions at which an enzyme works best?

Optimum

Name the process where genetic information (DNA) can be transferred from one cell to another

Genetic engineering

In genetic engineering what is identified at and then extracted from the source chromosome?

A gene

Name the small circular pieces of DNA that are extracted from bacterial cells in genetic engineering?

Plasmid

Name two products name using genetic engineering

Insulin, growth hormone, new antibiotics.

What types of proteins cut the gene from the DNA and then seals it into the plasmid?

Enzymes

What do you do with the modified plasmid in genetic engineering?

Put it into a host bacterial cell to produce a GM organism.

Name the process where chemical energy stored in glucose is released by a series of enzyme-controlled reactions.

Respiration

Name the high energy molecule which is regenerated in aerobic respiration.

ATP

ATP is regenerated from which two molecules

ADP and Pi

State three uses for the energy released from food during respiration

Cell division, protein synthesis, muscle contraction, generation of nerve impulses, photosynthesis

What type of respiration generates the most ATP from the full breakdown of a glucose molecule?

aerobic respiration

Write the word equation for aerobic respiration.

glucose + oxygen --> carbon dioxide + water + a large amount of ATP

What is the first stage of respiration called? Describe what happens in this stage.

Glycolysis, glucose is split into two molecules of pyruvate.

Two molecules of ATP are regenerated from ADP + Pi

Where does the first part of aerobic respiration / fermentation take place?

Cytoplasm

Where does the second stage of aerobic respiration take place?

Mitochondria

In the absence of oxygen, what respiratory pathway takes place?

Fermentation

Write the word equation for the fermentation pathway in animals and bacteria

glucose --> lactate + 2 ATP

Write the word equation for the fermentation pathway in plants or fungi

glucose --> carbon dioxide + ethanol + 2 ATP

What is a respirometer?

Apparatus that is used to measure the rate of respiration of an organism by measuring the oxygen uptake

What would be a suitable control for a respirometer?

Set up the respirometer exactly as the original experiment but use a dead version of the organism / glass beads that are the same mass as the organism.