Biology Exam Flashcards

Animal cell ultrastructure

cytoplasm, mitochondrion, nucleus, ribosome, cell membrane

Plant cell ultrastructure

cell wall, cytoplasm, mitochondrion, nucleus, ribosome, cell membrane, vacuole, chloroplasts

Fungal cell ultrastructure

nucleus, mitochondrion, cell membrane, ribosome, mitochondrion, cytoplasm, cell wall, vacuole

Bacterial cell ultrastructure

plasmid, cell membrane, ribosomes, cell wall, cell membrane, circular chromosome

What is the Nucleus' function?

contains genetic information and controls cell activities

What is the Plasmid' function?

A small ring of genetic material found in bacterial cell

What is the cell membrane' function?

a selectively permeable membrane that controls what goes in and out of the cell

What is the cytoplasm' function?

stores the cells organelles and is the site for chemical reactions

What is the cell wall' function?

outer layer of the cell that helps support it

What is the chloroplast' function?

makes carbohydrates in green plant cells using light energy in photosynthesis

What is the mitochondria' function?

the main site of ATP production in aerobic respiration in cells

What is the vacuole' function?

membrane bound sac that stores nutrients(water, salts and sugars) in cells

What is the ribosome' function?

the site of protein synthesis

1mm\=\__________μm

1000

The cell wall in plant cells is made up of \____________ molecules

cellulose

The cell membrane is made up of...

phospholipids + proteins

the cell membrane is \______________ permeable

selectively

What is active transport?

movement of molecules across a cell membrane against a concentration gradient with energy

What is passive transport?

The movement of materials across the cell membrane down a concentration gradient without energy

examples of passive transport

diffusion and osmosis

What is diffusion?

the movement of molecules from high to low concentration

What is osmosis?

the diffusion of water across a selectively permeable membrane from an area of high concentration to low concentration

Why is diffusion important?

needed to diffuse nutrients and food for broth and for respiration

If the water concentration outside an animal cell is higher than inside...

water passes in and it can burst

If the water concentration outside a plant cell is higher than inside...

water will pass in and it will become turgid

If the water concentration outside an animal cell is lower than inside...

water passes out and the cell shrinks

If the water concentration outside a plant cell is lower than inside...

water passes out and it becomes plasmolysed

describe the structure of dna

a double stranded held by complimentary base pairs

what does dna do?

Stores genetic information and codes for protein

What are the four DNA bases?

Adenine, Thymine, Guanine, Cytosine

A is always paired with

T

G is always paired with

C

What is a genetic code?

sequence of bases in DNA

A gene is a

segment of DNA that codes for a protein

What are amino acids?

the building blocks of proteins

What is a gene?

A section of DNA that codes for a protein

What does mRNA stand for?

messenger ribonucleic acid

How are proteins made?

transcription and translation

A proteins function is dependent on its....

shape

How do ribosomes make proteins?

They read 3 sections of RNA at a time while translating them into a chain of amino acids to make a protein.

How much of your body is proteins?

17%

What happens when you change the order of amino acids?

you get a different protein

Name the 5 protein functions

structural, enzymes, hormones, antibodies and receptors

What are enzymes?

biological catalysts

What do enzymes do?

speed up chemical reactions

The shape of the active site on an enzyme molecule is complementary to what?

its specific substrate

Enzyme action results in

products

What is a degradation reaction?

Then a large, complex substrate is broken down into smaller, simple products.

What is a synthesis reaction?

When small, simple substrates are built up into a large, complex product.

Draw a degradation reaction

Draw a synthesis reaction

What is amylase's substrate?

starch

What is carbohydrase's substrate?

carbohydrate

What can enzymes be affected by?

temperature and pH

What is a denatured enzyme?

A denatured enzyme is an enzyme that loses its shape and can no longer function properly.

State the substrate and product for the enzyme amylase

starch --\> maltose

State the substate and product for the enzyme Catalase

hydrogen peroxide --\> oxygen + water

State the substate and product for the enzyme pepsin

Protein --\> amino acids

Stages of genetic engineering

-identify section of DNA thats contains required gene from source chromosome
-extract required gene
-insert required gene into plasmid
-insert plasmid into host cell and grow modified cells to produce genetically modified organism

What is genetic engineering?

The manual transfer of DNA from one organism to another using biotechnology

What is respiration?

A chemical reaction in which energy is released from the breakdown of glucose

Cellular activities that require ATP

muscle contraction, cell division, protein synthesis

Glucose is broken down into

2 molecules of pyruvate

What does aerobic respiration do to pyruvate?

Glucose + oxygen \---\> carbon dioxide + water + energy

Aerobic respiration takes place when...

oxygen is present

Fermentation takes place when...

oxygen is not present

In animal cells the pyruvate molecules are converted into...

Glucose \---\> lactate + energy

In plant and yeast cells the pyruvate molecules are converted into...

Glucose \---\> carbon dioxide + ethanol + energy.

Where does respiration begin?

cytoplasm

What is the difference between where aerobic respiration and fermentation are completed?

aerobic respiration is completed in the mitochondria and fermentation is completed in the cytoplasm

What do structural proteins do?

Offers support to the cell/organisms

What do hormones do?

Act as chemical messengers in the body

What do antibodies do?

Combine with pathogens to destroy them and protect the body from disease

What do receptors do?

Receptors are found not he surface of cells + and allow signals to be transmitted across the cell membrane and into the cell

Does aerobic respiration have a high or low ATP yield?

High ATP yield

Does fermentation have a high or low ATP yield?

Low ATP yield

What is a respirometer?

A respirometer is a piece of equipment that can be used to investigate the rate at which an organism respires.

What are 4 things cells need to constantly reproduce for?

growth, repair of damaged cells, replacement of dead/damaged cells, maintains diploid chromosome compliment.

What is the term given to the division of a cell to produce new cells?

Mitosis (cell division)

What is mitosis?

Mitosis the process where the nucleus divides into identical daughter nuclei.

Stage 1 of Mitosis

Prior to mitosis chromosomes appear as fine threads scattered through the nucleus

Stage 2 of mitosis

At the start of mitosis chromosomes shorten + can be seen as 2 chromatids joined by a centromere

Stage 3 of mitosis

Chromosomes line up at the equator of the cell

Stage 4 of mitosis

Chromosomes split and chromatids move to opposite poles of the cell

Stage 5 of mitosis

Nuclear membrane forms around each of the chromosomes and two new nuclei are formed

Stage 6 of mitosis

Cytoplasm divides and two new daughter cells are formed

What are the three reasons that cells need to divide?

- Growth
- Repair of damaged tissues
- Replacement of damaged or dead tissues

Which cells have the opportunity to tur n into other cells??

Stem cells are unpecialised cells that are involved in growth and repair

What are the two things stem cells can do?

- can divide and self renew
- they have the potential to become different types of cell

What are the two types of stem cells?

Embryonic and tissue stem cells

What is the organism hierarchy?

cells -\> tissues -\> organs -\> systems

What does the central nervous system consist of?

brain and spinal cord

Where is the cerebrum located?

top of brain

Where is the medulla located?

the base of the brainstem

Where is the cerebellum located?

back of brain

Function of cerebrum

controls thought, memory, reasoning and muscle movement

Function of cerebellum

controls balance and coordination

Function of the medulla

Controls breathing and heart rate

What are the three types of neurons?

sensory, motor, inter

What is a synapse?

a gap between neurone