UnicodeEncodeError: 'ascii' codec can't encode character '\u030c' in position 142: ordinal not in range(128)

Question

import json
import codecs
from urllib.request import urlopen

url = "https://translate.yandex.net/api/v1.5/tr.json/translate?key=myapikeyhere&lang=hr-en&text="
word_list = codecs.open("inputfile.txt", encoding='utf-8').read().split(" ")
recnik = codecs.open('translation.txt', encoding='utf-8', mode='w')

for search_term in word_list:
    response = urlopen(url+search_term)
    translation = json.loads(response.readall().decode('utf-8'))
    translation = translation['text'][0]
    one_string = search_term + " " + translation + '\n'

    recnik.write(one_string)

I'm trying to translate a few words I have in a text file using yandex.ru's API. After the first few words are translated I get the following error:

UnicodeEncodeError: 'ascii' codec can't encode character '\u030c' in position 142: ordinal not in range(128)

It happens when it encounters the first word in my wordlist with a non ascii character. As far as I know I'm doing everything in unicode, but I am probably missing something obvious and I would appreciate someone else's eyes on this.

Error occurs on this line:

response = urlopen(url+search_term) 

EDIT:

The solution I used in case it can help somebody in the future:

import json
import codecs
from urllib.request import urlopen
from urllib.parse import quote 

url = "https://translate.yandex.net/api/v1.5/tr.json/translate?key=myapikey=hr-en&text="
word_list = codecs.open("inputfile.txt", encoding='utf-8').read().split(" ")
recnik = codecs.open('translation.txt', encoding='utf-8', mode='w')

for search_term in word_list:
    send = url+quote(search_term)
    response = urlopen(send)
    translation = json.loads(response.readall().decode('utf-8'))
    translation = translation['text'][0]
    one_string = search_term + " " + translation
    print(one_string)
    one_string += '\n'
    recnik.write(one_string)