CAPE Biology Unit 1 - Cell and Molecular Biology, Genetics and Variation, and Reproductive Biology Flashcards

Flashcards covering topics from CAPE Biology Unit 1, including biochemistry, cell structure, enzymes, nucleic acids, cell division, inheritance, genetic engineering, natural selection, and reproduction in plants and animals.

What property of water allows for temperature regulation?

Its high specific heat capacity and ability to evaporate easily.

What property of water makes it a universal solvent?

Its tiny charges attract other molecules or ions to form bonds.

What property of water allows for mass flow?

Its H-bonds produce cohesion and surface tension.

What is the general formula for a monosaccharide?

(CH2O)n

What two monosaccharides combine to form sucrose?

Alpha glucose and beta fructose

Why is sucrose used for transport instead of glucose in plants?

It is much more complex, more energy-efficient, and not as reactive as glucose.

What are the two polymers that make up starch?

Amylose and amylopectin

Where is glycogen usually found in animals?

The liver and in muscles

What type of bonds are found in cellulose?

β 1-4 glycosidic bonds

What distinguishes lipids from carbohydrates chemically?

Lipids contain a much higher proportion of hydrogen.

What two products result from the breakdown of fats?

Fatty acids and glycerol

What type of bond is formed between the carboxyl groups of fatty acids and the hydroxyl groups of glycerol in a triglyceride?

Ester bond

What is the key structural difference between saturated and unsaturated fats?

Unsaturated fats have at least one carbon atom double-bonded to another, reducing the amount of hydrogen it holds.

What two components make up phospholipids?

A phosphate group and two fatty acids attached to a glycerol molecule

What type of bond links amino acids together?

Peptide bonds

Where in the cell does protein synthesis occur?

Ribosomes

What are the four levels of protein structure?

Primary, secondary, tertiary, and quaternary

Name the four types of bonds involved in tertiary protein structure.

Hydrogen, disulphide, ionic, and hydrophobic interaction

Name four reducing sugars

Glucose, maltose, fructose and lactose

Name a non-reducing sugar

Sucrose

What reagent is used to test for reducing and non-reducing sugars?

Benedict’s solution

What reagent is used to test for starch?

Iodine solution in potassium iodide (KI/I2)

What reagent is used to test for proteins?

Biuret reagent

What is the outcome of a lipid test?

An opaque milky white layer of droplets that float to the top called an emulsion

What are two types of electron microscopes?

Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM)

What is a key difference between light microscopes and electron microscopes regarding specimen preparation?

Light microscopes can use living cells and tissues, while electron microscopes use only non-living and dehydrated cells.

What is the term used when an electron microscope is used to view cell structure?

Ultrastructure

What structure is present in plant cells but absent in animal cells?

Chloroplasts

What is the function of the nucleolus?

It contains ribosomal RNA (rRNA), which helps with protein synthesis.

What two types of cells don’t have nuclei?

Red blood cells and phloem sieve tubes.

What process occurs in the cristae of the mitochondria?

Aerobic respiration

What are the stacks of thylakoids in chloroplasts called?

Grana

What is the middle lamella composed of and what is its function?

Pectin which holds cells together

What type of endoplasmic reticulum has ribosomes attached to it?

Rough ER (RER)

What process does the Golgi body use to transport materials to the plasma membrane and then outside the cell?

Exocytosis

What does the 'S' in 70S and 80S ribosomes stand for?

Svedberg unit, which is a measure of how fast a particle settles in a solution.

What are two organisms that are prokaryotes?

Bacteria and archaea

What is the primary component of the cell wall in prokaryotic cells (e.g., bacteria)?

Peptidoglycan

Name three pieces of evidence for the endosymbiosis theory.

Own DNA, similar ribosomes to prokaryotes, pair of membranes

What is a tissue?

A group of cells that carry out the same function.

Where does water move when entering a plant root?

To the centre of the root through cell walls or cells in the cortex/parenchyma

What is the waterproof layer in the endodermis of a plant root, and what is its purpose?

Casparian strips that limits capillary action

What tissue is responsible for secondary growth of stems?

Cambium

What type of drawing depicts the general structure and main parts of a specimen without illustrating the complexity of cell arrangement?

Plan Drawing

What phrase describes the structure of the plasma membrane?

Fluid mosaic model.

What molecule maintains the fluidity of the membrane throughout extremes in temperature?

Cholesterol

What is glyocolyx?

If the outer surface of the membrane is covered with glycoproteins or glycolipids. Glycoproteins and glycolipids can act as receptor sites to allow binding of certain molecules such as HORMONES or NEUROTRANSMITTERS.

What is passive transport?

Movement of molecules into and out of the cells with no use of ATP.

What is active transport?

Movement of molecules into and out of the cells with the use of ATP.

What two processes are examples of passive transport?

Diffusion and facilitated diffusion

What is facilitated diffusion?

Diffusion requires the use of specific pathways called CHANNEL PROTEINS, which form hydrophilic passages.

What causes the rate of facilitated diffusion to reach a peak?

Since facilitated diffusion requires the use of protein channels which decreases over time

What does a symport do?

Carrier protein that moves 2 molecules together in the same direction

What does an antiport do?

Carrier protein that moves 2 molecules together in the opposite direction

What type of transport is used for bulk movement of materials across the membrane?

Exocytosis and endocytosis

What process removes toxins from the cell’s interior?

Exocytosis

What endocytosis process involves absorbing masses of fluid into the cell

Pinocytosis

What term describes a shrivelling cell?

Crenation

What term describes a bursting cell?

Lysis

What does water potential measures

The tendency of water to leave the solution

What happens to a plant tissue with too much solute?

If there is too much solute in the cell, water will leave and the cell loses turgor and is said to have undergone plasmolysis. There is a point where the cell loses enough internal water pressure that it stops pressing against the cell wall. As a result, the cell wall stops pushing back.

What occurs during incipient plasmolysis?

When the plasma membrane will begin to retract. Also, the pint where the water potential inside is equal to the solute potential inside.

What is an enzyme?

Globular proteins that act as biological catalysts to speed up chemical reactions.

What is metabolism?

All the chemical reactions that occur in the body.

What is anabolism?

The combination of small molecules to produce larger, more complex molecules.

What is catabolism?

The breakdown of larger molecules to produce smaller, simpler molecules.

What enzyme breaks down toxic hydrogen peroxide in the body?

Catalase

What are the lock and key and induced fit mechanisms?

The substrates are always in motion due to their kinetic energy, so think of them as rapidly colliding with the enzymes until they bind. The active site has R groups that interact with the substrate. The substrate temporarily binds with the enzyme’s active site, which is a specific shape on the enzyme’s surface. This is often referred to as a lock and key mechanism if it is a perfect fit. However, some enzymes alter their shape slightly to accommodate holding the substrate in place. This is known as induced fit.

What is the maximum number of substrate molecules that can be converted to product per minute known as?

Enzyme's turnover number

What is denaturing an enzyme?

Enzyme can be permanently altered and would not work. It would experience denaturation

What is the slope at when measuring the rate of reaction called?

Intial Rate of Reaction

How does temperature affect enzyme activity?

Reaction rate is actually said to DOUBLE every 10oC increase

What happens in terms of enzyme reactions as temperature increases?

Enzyme vibrates too energetically and the tertiary protein structure of the enzyme begins to break down. This is because high temperatures BREAK THE HYDROGEN BONDS that hold the structure together.

What are two mammalian proteases found in the human body?

Pepsin and trypsin

At what pH does pepsin operate?

Acidic pH

At what pH does trypsin operate?

Alkaline pH

What is an enzyme inhibitor?

Non-competitive inhibition, can be either reversible or irreversible, and increasing the amount of substrate has no effect, whatsoever, as the enzyme itself has changed.

What site might an enzyme hav aside from an active site?

Alosteric site

What is a key difference competitively and non-competitively inhibiting an enzyme?

Competitive inhibition is usually reversible and binds at an action site, while non-competitive has a higher tendency to be irreversible as there is a higher chance of permanent distortion of enzyme and binds at an alosteric site.

Name 3 competitive inhibitors

Antabuse, penicillin and malonate

Name 3 non-competitive inhibitors

Malathion, digitalis and alpha-amanitin

What are purines?

A and G, and have two rings

What are pyrimidines?

C and T, and have one ring

What forms a phosphodiester bond?

When the phosphate links with the sugar forming a condensation reaction.

What does antiparallel mean?

Both chains actually run in opposite directions (notice the inverted sugars)

What base pairs are linked together with hydrogen bonds?

A can only pair with T and C can only pair with G.

What is the role of DNA helicase in DNA replication?

Unzips the DNA into two strands by breaking the hydrogen bonds between the bases.

Which base pair subsitutes in RNA?

Uracil (U) replaces Thymine (T).

What is the name for one old strand (the original) and one
new strand (the one built by DNA polymerase)?

Semiconservative replication.

What did the Mieselson and Stahl prove about semicopnservative replication?

That DNA was built by separating parent strands and adding new nucleotides to form complementary strands on the new templates.

What role does RNA play in protein synthesis?

Help transfer an amino acid molecule towards mRNA and build polypeptides

What are euchromatin?

Lighter-coloured and less tightly- coiled, as it is prepared for transcription

What are heterochromatin?

More tightly coiled, denser and darker in colour, this is found in DNA not being used for transcription.

How many pairs of homologous chromosomes do humans have?

22

Which phase involves Dna being replicated?

Interphase

Where does genetic variation occur during meiosis?

Undergo genetic variation due to crossing over, independent assortment and random segregation.

What happens during Anaphase II in comparison to Anaphase I?

sister chromatids are pulled apart while there is a halving of chromosomes

What causes Sickle Cell Anaenia to occur?

Substitution

Name three ways how gene mutations can occur.

Insertion, deletion and substitution

What are Auenploidy caused by?

Down syndrome, Klinefelter syndrome and turner syndrome