Biology Final Exam

How does oxidation affect the C-H bonds?

it decreases the C-H bonds (carbon-hydrogen)

(it increases the C-O bonds (carbon-oxygen))

What is Homonymy?

refers to a situation where two or more scientific names are identical in spelling but refer to different taxa

Open circulation

Insects (Invertebrates)

What molecules are hydrophilic?

carbohydrates (polar)

Hydrophobic

lipids

Microevolution

natural selection, mutation, gene flow, genetic drift

Macroevolution

speciation, extinction, evolution of life on Earth

light-independent reactions

sets of reactions in photosynthesis that do not require light as it takes place in the stoma

energy from ATP and NADPH is used to build high-energy compounds such as sugars (Calvin cycle)

How many gap phases are in a cell cycle?

2

What is Autopolyploidy?

an individual that has more than two chromosome sets that are all derived from a single species

How many chromosomes are there in Polyploidy?

more than two complete chromosome sets

Amphiphilic

molecules that contain both polar hydrophilic (water-attracting) and nonpolar hydrophobic (water-repelling) parts e.g. phospholipids

Chemiosmosis

occurs in cells, particularly in the mitochondria and chloroplasts, during which a proton gradient is used to generate ATP
- links the electron transport chain and the production of ATP by harnessing the energy stored in the proton gradient across membranes

What is the function of the endoplasmic reticulum?

essential in lipid and protein synthesis

What carries amino acids to the ribosomes?

tRNA (transfer RNA)

What defines genetic code?

information encoded in genetic material (DNA or RNA) is translated into proteins

The code defines how sequences of nucleotide triplets, called codons, specify which amino acid will be added next during protein synthesis

always reads from 5 ‘to 3‘

What are Telomeres?

structures found at the ends of chromosomes, consisting of repetitive sequences of DNA and associated proteins

Lysosomes are almost absent in:

plant cells (they have vacuoles)

ATP is produced with the help of

Mitochondria

What is Anabolism?

uses energy and building blocks to build large molecules
energy is required
e.g. photosynthesis is an anabolic pathway (builds sugars out of smaller molecules)

What is Catabolism?

larger molecules are broken down into small ones, energy is released
e.g. cellular respiration is a catabolic pathway

Plant hormones: Strigolactones

Produced by a plant's roots - promote the growth of symbiotic arbuscular mycorrhizal (AM) fungi

Plant hormones: Salicylic acid

- a critical role in the defense against biotrophic pathogens
- the precursor of the painkiller, aspirin

Plant hormones: Ethylene

- Gas with very limited solubility in water
- Affects cell growth and cell shape; preventing cell elongation and causing the stem to swell

Plant hormones: Abscisic acid

growth inhibitor

Plant hormones: Cytokinins

chemicals that influence cell division and shoot formation

Plant hormones: Gibberellins

they control multiple aspects of development across the life cycle

Plant hormones: Auxins

- Positively influence cell enlargement, bud formation and root initiation
- support the production of other hormones
- with cytokinins, they control the growth of stems, roots, and fruits, and convert stems into flowers
- The auxin transport system provides positional and
directional information for many aspects of adaptive plant
development

Chlorplast vs. Mitochondria membrane

Mitochondria:

- mitochondrial membrane is made up of two distinct phospholipid bilayers

- outer membrane is more permeable than inner membrane - allows fast distribution of molecules

Chloroplast:

- Chloroplast also has two membranes (highly permeable outer membrane - much less permeable inner membrane)

- inner membrane is not folded in cristae and does not

contain electron-transport chains like in Mitochondria

What is rRNA?

ribosomal RNA - makes up part of the ribosomes

What is mRNA?

messenger RNA - carries instructions from DNA in the nucleus to the ribosome

Translation

synthesizes proteins in the cytoplasm of the cell, specifically at the ribosomes

Transcription

a specific segment of DNA is used as a template to synthesize mRNA in the nucleus - this mRNA carries the genetic information from the DNA and serves as a messenger to the cytoplasm

Nucleotides

link together to form long chains or strands in DNA and RNA

Founder effect

loss of genetic variation (part of genetic drift)
e.g. migration of a set belonging to the original population

Bottleneck effect

sudden change in population size (changes in allele proportions) - part of genetic drift
e.g. environmental catastrophe

passive transport

down the concentration/electrochemical gradient

active transport

against concentration/electrochemical gradient

Photorespiration

a wasteful pathway that occurs when the Calvin cycle enzyme rubisco acts on oxygen rather than carbon dioxide

purpose of the Calvin cycle

to be able to have a store of energy in the form of glucose (converting CO2 into organic molecules)

Mycorrhizaes

mutually beneficial associations between fungi and the roots of most plants

Ectomycorrhizae

fungal hyphae form a sheath around the outside of the plant root and grow between the cells without penetrating the cell walls

Mycorrhizae acts as:

root hair in adverse conditions

Mycorrhizae promotes plant growth by:

serving as plant growth regulator

Endomycorrhizae is found in what types of plants:

all types of plants (terrestrial)

Mesophyll

forms the body of a leaf and carries on photosynthesis

Xylem

vascular tissue that transports water and minerals upward through the plant body

Stoma

Allows the plant to breath and transpire - gives off
moisture

Phloem

Products of photosynthesis prepared in the leaves are to be transported to the rest of the plant by the food carrying tubes

Plant hormones strigolactones

Endomycorrhizae (Arbuscular mycorrhizae) works through the hormones strigolactones e.g. works against weed in agriculture

Chemiosmotic coupling

movement of ions across a semipermeable membrane bound structure, down their electrochemical gradient -

describes the process that links the electron transport chain, which creates an electrochemical gradient across the inner mitochondrial membrane, to the production of ATP through the molecular machine ATP synthase

e.g. movement of hydrogen ions (H+) across a membrane during cellular respiration or photosynthesis.

CAM plants

open their stomata at night, incorporating CO2 into organic acids

Mitochondrial DNA

DNA is circular in shape
contain regions that are single-stranded

Homology

similarity resulting from common ancestry